Rewrite union type print (#18827)

changelog_unreleased/typescript/18827-2.md

@@ -0,0 +1,19 @@
+#### Don't break union type when it can fit (#18827 by @fisker)
+
+<!-- prettier-ignore -->
+```tsx
+// Input
+type Browser = "chromium" | "webkit" | "firefox" | "chromium-msedge" | "chromium-chrome";
+
+// Prettier stable
+type Browser =
+  | "chromium"
+  | "webkit"
+  | "firefox"
+  | "chromium-msedge"
+  | "chromium-chrome";
+
+// Prettier main
+type Browser =
+  "chromium" | "webkit" | "firefox" | "chromium-msedge" | "chromium-chrome";
+```

changelog_unreleased/typescript/18827.md

@@ -0,0 +1,22 @@
+#### Remove extra indention for union type in conditional type (#18827 by @fisker)
+
+<!-- prettier-ignore -->
+```tsx
+// Input
+type A = T extends "arrow"
+  ? ExcalidrawArrowElement["startBinding"] | ExcalidrawElbowArrowElement["startBinding"]
+  : never;
+
+// Prettier stable
+type A = T extends "arrow"
+  ?
+      | ExcalidrawArrowElement["startBinding"]
+      | ExcalidrawElbowArrowElement["startBinding"]
+  : never;
+
+// Prettier main
+type A = T extends "arrow"
+  ? | ExcalidrawArrowElement["startBinding"]
+    | ExcalidrawElbowArrowElement["startBinding"]
+  : never;
+```

src/language-js/print/assignment.js

@@ -28,6 +28,7 @@ import {
 } from "../utilities/node-types.js";
 import { shouldInlineLogicalExpression } from "./binaryish.js";
 import { printCallExpression } from "./call-expression.js";
+import { shouldHugUnionType } from "./union-type.js";
 
 /**
  * @import AstPath from "../../common/ast-path.js"
@@ -136,6 +137,7 @@ function chooseLayout(path, options, print, leftDoc, rightPropertyName) {
 
   if (
     isHeadOfLongChain ||
+    (isUnionType(rightNode) && !shouldHugUnionType(rightNode)) ||
     hasLeadingOwnLineComment(options.originalText, rightNode)
   ) {
     return "break-after-operator";

src/language-js/print/flow.js

@@ -53,7 +53,7 @@ import { printTypePredicate } from "./type-predicate.js";
 import { printTypeQuery } from "./type-query.js";
 import { printUnionType } from "./union-type.js";
 
-function printFlow(path, options, print) {
+function printFlow(path, options, print, args) {
   const { node } = path;
 
   if (isFlowKeywordType(node)) {
@@ -117,7 +117,7 @@ function printFlow(path, options, print) {
     case "IntersectionTypeAnnotation":
       return printIntersectionType(path, options, print);
     case "UnionTypeAnnotation":
-      return printUnionType(path, options, print);
+      return printUnionType(path, options, print, args);
     case "ConditionalTypeAnnotation":
       return printTernary(path, options, print);
     case "InferTypeAnnotation":

src/language-js/print/typescript.js

@@ -45,7 +45,7 @@ import { printTypePredicate } from "./type-predicate.js";
 import { printTypeQuery } from "./type-query.js";
 import { printUnionType } from "./union-type.js";
 
-function printTypescript(path, options, print) {
+function printTypescript(path, options, print, args) {
   const { node } = path;
 
   // TypeScript nodes always starts with `TS`
@@ -186,7 +186,7 @@ function printTypescript(path, options, print) {
     case "TSIntersectionType":
       return printIntersectionType(path, options, print);
     case "TSUnionType":
-      return printUnionType(path, options, print);
+      return printUnionType(path, options, print, args);
     case "TSFunctionType":
     case "TSCallSignatureDeclaration":
     case "TSConstructorType":

src/language-js/print/union-type.js

@@ -12,13 +12,13 @@ import {
   printCommentsSeparately,
 } from "../../main/comments/print.js";
 import needsParentheses from "../parentheses/needs-parentheses.js";
-import { CommentCheckFlags, hasComment } from "../utilities/comments.js";
+import { hasComment } from "../utilities/comments.js";
 import { createTypeCheckFunction } from "../utilities/create-type-check-function.js";
-import { hasLeadingOwnLineComment } from "../utilities/has-leading-own-line-comment.js";
+import { isFlowObjectTypePropertyAFunction } from "../utilities/is-flow-object-type-property-a-function.js";
 import {
   isConditionalType,
   isTupleType,
-  isTypeAlias,
+  isTypeParameterInstantiation,
 } from "../utilities/node-types.js";
 import { shouldUnionTypePrintOwnComments } from "../utilities/should-union-type-print-own-comments.js";
 
@@ -27,7 +27,7 @@ import { shouldUnionTypePrintOwnComments } from "../utilities/should-union-type-
 */
 
 // `TSUnionType` and `UnionTypeAnnotation`
-function printUnionType(path, options, print) {
+function printUnionType(path, options, print, args) {
   const { node } = path;
   // single-line variation
   // A | B | C
@@ -39,33 +39,6 @@ function printUnionType(path, options, print) {
 
   const { parent } = path;
 
-  // If there's a leading comment, the parent is doing the indentation
-  const shouldIndent =
-    parent.type !== "TypeParameterInstantiation" &&
-    parent.type !== "TSTypeParameterInstantiation" &&
-    parent.type !== "GenericTypeAnnotation" &&
-    parent.type !== "TSTypeReference" &&
-    parent.type !== "TSTypeAssertion" &&
-    !isTupleType(parent) &&
-    !(
-      parent.type === "FunctionTypeParam" &&
-      !parent.name &&
-      path.grandparent.this !== parent
-    ) &&
-    !(
-      isConditionalType(parent) &&
-      !options.experimentalTernaries &&
-      hasLeadingOwnLineComment(options.originalText, node)
-    ) &&
-    !(
-      (isTypeAlias(parent) || parent.type === "VariableDeclarator") &&
-      hasLeadingOwnLineComment(options.originalText, node)
-    ) &&
-    !(
-      isTypeAlias(parent) &&
-      hasComment(parent.id, CommentCheckFlags.Trailing | CommentCheckFlags.Line)
-    );
-
   // {
   //   a: string
   // } | null | void
@@ -97,32 +70,65 @@ function printUnionType(path, options, print) {
     return [leading, join(" | ", printed), trailing];
   }
 
-  const shouldAddStartLine =
-    shouldIndent && !hasLeadingOwnLineComment(options.originalText, node);
-
   const mainParts = [
-    ifBreak([shouldAddStartLine ? line : "", "| "]),
-    join([line, "| "], printed),
+    leading,
+    group([ifBreak("| "), join([line, "| "], printed)]),
+    trailing,
   ];
 
   if (needsParentheses(path, options)) {
-    return [leading, group([indent(mainParts), softline]), trailing];
+    return group([indent([softline, mainParts]), softline]);
   }
 
-  const parts = [leading, group(mainParts)];
-
   if (isTupleType(parent) && parent.elementTypes.length > 1) {
     return [
       group([
-        indent([ifBreak(["(", softline]), parts]),
+        indent([ifBreak(["(", softline]), mainParts]),
         softline,
         ifBreak(")"),
       ]),
-      trailing,
     ];
   }
 
-  return [group(shouldIndent ? indent(parts) : parts), trailing];
+  // Already indent in parent
+  if (
+    args?.assignmentLayout === "break-after-operator" ||
+    !shouldIndentUnionType(path)
+  ) {
+    return mainParts;
+  }
+
+  return group(indent([softline, mainParts]));
+}
+
+function shouldIndentUnionType(path) {
+  const { key, parent } = path;
+  if (
+    (key === "typeAnnotation" && parent.type === "TSTypeAssertion") ||
+    (key === "elementTypes" && isTupleType(parent)) ||
+    ((key === "trueType" || key === "falseType") &&
+      isConditionalType(parent)) ||
+    (key === "params" && isTypeParameterInstantiation(parent))
+  ) {
+    return false;
+  }
+
+  if (
+    path.match(
+      undefined,
+      (node, key) =>
+        key === "typeAnnotation" && node.type === "FunctionTypeParam",
+      (node, key) => key === "params" && node.type === "FunctionTypeAnnotation",
+      (node, key) =>
+        key === "value" &&
+        node.type === "ObjectTypeProperty" &&
+        isFlowObjectTypePropertyAFunction(node),
+    )
+  ) {
+    return false;
+  }
+
+  return true;
 }
 
 const isVoidType = createTypeCheckFunction([

src/language-js/utilities/node-types.js

@@ -137,4 +137,9 @@ export const isArrayType = createTypeCheckFunction([
   "ArrayTypeAnnotation",
 ]);
 
+export const isTypeParameterInstantiation = createTypeCheckFunction([
+  "TSTypeParameterInstantiation",
+  "TypeParameterInstantiation",
+]);
+
 export * from "./literal.js";

tests/config/format-test/failed-format-tests.js

@@ -25,7 +25,6 @@ const unstableTests = new Map(
     "js/sequence-expression/parenthesized.js",
     "typescript/satisfies-operators/comments-unstable.ts",
     "jsx/comments/in-attributes.js",
-    "typescript/union/consistent-with-flow/single-type.ts",
     "typescript/import-type/long-module-name/long-module-name4.ts",
     // Unstable due to lack of indent information
     "js/multiparser-comments/comment-inside.js",

tests/format/flow/as-satisfies-expression/__snapshots__/format.test.js.snap

@@ -87,8 +87,7 @@ const value1 =
 const value2 =
   thisIsAnIdentifier as thisIsAReallyReallyReallyReallyReallyReallyReallyReallyReallyReallyReallyLongInterface;
 const value3 = thisIsAReallyLongIdentifier as
-  | SomeInterface
-  | SomeOtherInterface;
+  SomeInterface | SomeOtherInterface;
 const value4 = thisIsAReallyLongIdentifier as {
   prop1: string,
   prop2: number,

tests/format/flow/comments/normal-comments/__snapshots__/format.test.js.snap

@@ -13,7 +13,8 @@ type Foo = {
 
 =====================================output=====================================
 type Foo = {
-  bar: // test
+  bar:
+    // test
     | { loooooooooooooooooongPropName1: string }
     | { loooooooooooooooooongPropName2: string },
 };

tests/format/flow/flow-repo/call_caching1/lib/__snapshots__/format.test.js.snap

@@ -41,8 +41,7 @@ declare class Array<T> {
 }
 
 type IteratorResult<Yield, Return> =
-  | { done: true, value?: Return }
-  | { done: false, value: Yield };
+  { done: true, value?: Return } | { done: false, value: Yield };
 
 interface $Iterator<+Yield, +Return, -Next> {
   @@iterator(): $Iterator<Yield, Return, Next>;

tests/format/flow/flow-repo/disjoint-union-perf/__snapshots__/format.test.js.snap

@@ -1015,13 +1015,7 @@ export type BinaryOperator =
   | "..";
 
 export type UnaryOperator =
-  | "-"
-  | "+"
-  | "!"
-  | "~"
-  | "typeof"
-  | "void"
-  | "delete";
+  "-" | "+" | "!" | "~" | "typeof" | "void" | "delete";
 
 export type AssignmentOperator =
   | "="

tests/format/flow/union/__snapshots__/format.test.js.snap

@@ -12,7 +12,8 @@ const myValue = (callcallcallcallcallcall(87689769876876897698768768976987687689
 =====================================output=====================================
 const myValue = (callcallcallcallcallcall(
   87689769876876897698768768976987687689769876,
-): // Comment
+):
+  // Comment
   | one
   | two
   | thre

tests/format/typescript/as/__snapshots__/format.test.js.snap

@@ -104,8 +104,7 @@ const value1 =
 const value2 =
   thisIsAnIdentifier as thisIsAReallyReallyReallyReallyReallyReallyReallyReallyReallyReallyReallyLongInterface;
 const value3 = thisIsAReallyLongIdentifier as
-  | SomeInterface
-  | SomeOtherInterface;
+  SomeInterface | SomeOtherInterface;
 const value4 = thisIsAReallyLongIdentifier as {
   prop1: string;
   prop2: number;

tests/format/typescript/as/break-after-keyword/__snapshots__/format.test.js.snap

@@ -44,8 +44,7 @@ const firstItem_1 = ______________.items.find(
 
 // 79 width until \`as\` or \`satisfies\` keyword
 const firstItem2 = ______________.items.find((item) => item.type === "item") as
-  | string
-  | number;
+  string | number;
 // 80 width until \`as\` or \`satisfies\` keyword
 const firstItem_2 = ______________.items.find(
   (item) => item.type === "item",
@@ -53,8 +52,7 @@ const firstItem_2 = ______________.items.find(
 
 // 79 width until \`as\` or \`satisfies\` keyword
 const firstItem3 = _____________.find((item) => item.type === "item") satisfies
-  | string
-  | number;
+  string | number;
 // 80 width until \`as\` or \`satisfies\` keyword
 const firstItem_3 = _____________.find(
   (item) => item.type === "item",

tests/format/typescript/conditional-types/__snapshots__/format.test.js.snap

@@ -88,6 +88,11 @@ T = any instanceof B
     // Multiline comment
     ? B | C
     : D;
+T = any instanceof B
+    ? D
+    // Comment
+    // Multiline comment
+    : B | C;
 
 type T = any extends B
     // Comment
@@ -201,8 +206,8 @@ c */
 type T =
   any extends B ?
     // Comment
-      // Multiline comment
-      B | C
+    // Multiline comment
+    B | C
   : D;
 T =
   any instanceof B ?
@@ -210,11 +215,16 @@ T =
     // Multiline comment
     B | C
   : D;
+T =
+  any instanceof B ? D
+    // Comment
+    // Multiline comment
+  : B | C;
 
 type T =
   any extends B ?
     // Comment
-      B | C
+    B | C
   : D;
 T =
   any instanceof B ?
@@ -225,9 +235,9 @@ T =
 type T =
   any extends B ?
     /**
-       * Comment
-       */
-      B | C
+     * Comment
+     */
+    B | C
   : D;
 T = any instanceof B ?
     /**
@@ -328,6 +338,11 @@ T = any instanceof B
     // Multiline comment
     ? B | C
     : D;
+T = any instanceof B
+    ? D
+    // Comment
+    // Multiline comment
+    : B | C;
 
 type T = any extends B
     // Comment
@@ -441,6 +456,12 @@ T =
       // Multiline comment
       B | C
     : D;
+T =
+  any instanceof B
+    ? D
+    : // Comment
+      // Multiline comment
+      B | C;
 
 type T = any extends B
   ? // Comment

tests/format/typescript/conditional-types/comments.ts

@@ -80,6 +80,11 @@ T = any instanceof B
     // Multiline comment
     ? B | C
     : D;
+T = any instanceof B
+    ? D
+    // Comment
+    // Multiline comment
+    : B | C;
 
 type T = any extends B
     // Comment

tests/format/typescript/conformance/types/union/__snapshots__/format.test.js.snap

@@ -101,45 +101,39 @@ unionOfDifferentReturnType1(true); // error in type of parameter
 unionOfDifferentReturnType1(); // error missing parameter
 
 var unionOfDifferentParameterTypes:
-  | { (a: number): number }
-  | { (a: string): Date };
+  { (a: number): number } | { (a: string): Date };
 unionOfDifferentParameterTypes(10); // error - no call signatures
 unionOfDifferentParameterTypes("hello"); // error - no call signatures
 unionOfDifferentParameterTypes(); // error - no call signatures
 
 var unionOfDifferentNumberOfSignatures:
-  | { (a: number): number }
-  | { (a: number): Date; (a: string): boolean };
+  { (a: number): number } | { (a: number): Date; (a: string): boolean };
 unionOfDifferentNumberOfSignatures(); // error - no call signatures
 unionOfDifferentNumberOfSignatures(10); // error - no call signatures
 unionOfDifferentNumberOfSignatures("hello"); // error - no call signatures
 
 var unionWithDifferentParameterCount:
-  | { (a: string): string }
-  | { (a: string, b: number): number };
+  { (a: string): string } | { (a: string, b: number): number };
 unionWithDifferentParameterCount(); // no  call signature
 unionWithDifferentParameterCount("hello"); // no  call signature
 unionWithDifferentParameterCount("hello", 10); // no  call signature
 
 var unionWithOptionalParameter1:
-  | { (a: string, b?: number): string }
-  | { (a: string, b?: number): number };
+  { (a: string, b?: number): string } | { (a: string, b?: number): number };
 strOrNum = unionWithOptionalParameter1("hello");
 strOrNum = unionWithOptionalParameter1("hello", 10);
 strOrNum = unionWithOptionalParameter1("hello", "hello"); // error in parameter type
 strOrNum = unionWithOptionalParameter1(); // error
 
 var unionWithOptionalParameter2:
-  | { (a: string, b?: number): string }
-  | { (a: string, b: number): number };
+  { (a: string, b?: number): string } | { (a: string, b: number): number };
 strOrNum = unionWithOptionalParameter2("hello"); // error no call signature
 strOrNum = unionWithOptionalParameter2("hello", 10); // error no call signature
 strOrNum = unionWithOptionalParameter2("hello", "hello"); // error no call signature
 strOrNum = unionWithOptionalParameter2(); // error no call signature
 
 var unionWithOptionalParameter3:
-  | { (a: string, b?: number): string }
-  | { (a: string): number };
+  { (a: string, b?: number): string } | { (a: string): number };
 strOrNum = unionWithOptionalParameter3("hello");
 strOrNum = unionWithOptionalParameter3("hello", 10); // error no call signature
 strOrNum = unionWithOptionalParameter3("hello", "hello"); // error no call signature
@@ -155,8 +149,7 @@ strOrNum = unionWithRestParameter1("hello", "hello"); // error in parameter type
 strOrNum = unionWithRestParameter1(); // error
 
 var unionWithRestParameter2:
-  | { (a: string, ...b: number[]): string }
-  | { (a: string, b: number): number };
+  { (a: string, ...b: number[]): string } | { (a: string, b: number): number };
 strOrNum = unionWithRestParameter2("hello"); // error no call signature
 strOrNum = unionWithRestParameter2("hello", 10); // error no call signature
 strOrNum = unionWithRestParameter2("hello", 10, 11); // error no call signature
@@ -164,8 +157,7 @@ strOrNum = unionWithRestParameter2("hello", "hello"); // error no call signature
 strOrNum = unionWithRestParameter2(); // error no call signature
 
 var unionWithRestParameter3:
-  | { (a: string, ...b: number[]): string }
-  | { (a: string): number };
+  { (a: string, ...b: number[]): string } | { (a: string): number };
 strOrNum = unionWithRestParameter3("hello");
 strOrNum = unionWithRestParameter3("hello", 10); // error no call signature
 strOrNum = unionWithRestParameter3("hello", 10, 11); // error no call signature
@@ -173,8 +165,7 @@ strOrNum = unionWithRestParameter3("hello", "hello"); // error no call signature
 strOrNum = unionWithRestParameter3(); // error no call signature
 
 var unionWithRestParameter4:
-  | { (...a: string[]): string }
-  | { (a: string, b: string): number };
+  { (...a: string[]): string } | { (a: string, b: string): number };
 strOrNum = unionWithRestParameter4("hello"); // error supplied parameters do not match any call signature
 strOrNum = unionWithRestParameter4("hello", "world");
 
@@ -366,8 +357,7 @@ var strOrNum: string | number;
 // If each type in U has construct signatures and the sets of construct signatures are identical ignoring return types,
 // U has the same set of construct signatures, but with return types that are unions of the return types of the respective construct signatures from each type in U.
 var unionOfDifferentReturnType:
-  | { new (a: number): number }
-  | { new (a: number): Date };
+  { new (a: number): number } | { new (a: number): Date };
 numOrDate = new unionOfDifferentReturnType(10);
 strOrBoolean = new unionOfDifferentReturnType("hello"); // error
 new unionOfDifferentReturnType1(true); // error in type of parameter
@@ -381,8 +371,7 @@ new unionOfDifferentReturnType1(true); // error in type of parameter
 new unionOfDifferentReturnType1(); // error missing parameter
 
 var unionOfDifferentParameterTypes:
-  | { new (a: number): number }
-  | { new (a: string): Date };
+  { new (a: number): number } | { new (a: string): Date };
 new unionOfDifferentParameterTypes(10); // error - no call signatures
 new unionOfDifferentParameterTypes("hello"); // error - no call signatures
 new unionOfDifferentParameterTypes(); // error - no call signatures
@@ -395,8 +384,7 @@ new unionOfDifferentNumberOfSignatures(10); // error - no call signatures
 new unionOfDifferentNumberOfSignatures("hello"); // error - no call signatures
 
 var unionWithDifferentParameterCount:
-  | { new (a: string): string }
-  | { new (a: string, b: number): number };
+  { new (a: string): string } | { new (a: string, b: number): number };
 new unionWithDifferentParameterCount(); // no  call signature
 new unionWithDifferentParameterCount("hello"); // no  call signature
 new unionWithDifferentParameterCount("hello", 10); // no  call signature
@@ -418,8 +406,7 @@ strOrNum = new unionWithOptionalParameter2("hello", "hello"); // error no call s
 strOrNum = new unionWithOptionalParameter2(); // error no call signature
 
 var unionWithOptionalParameter3:
-  | { new (a: string, b?: number): string }
-  | { new (a: string): number };
+  { new (a: string, b?: number): string } | { new (a: string): number };
 strOrNum = new unionWithOptionalParameter3("hello"); // error no call signature
 strOrNum = new unionWithOptionalParameter3("hello", 10); // error no call signature
 strOrNum = new unionWithOptionalParameter3("hello", "hello"); // error no call signature
@@ -444,8 +431,7 @@ strOrNum = new unionWithRestParameter2("hello", "hello"); // error no call signa
 strOrNum = new unionWithRestParameter2(); // error no call signature
 
 var unionWithRestParameter3:
-  | { new (a: string, ...b: number[]): string }
-  | { new (a: string): number };
+  { new (a: string, ...b: number[]): string } | { new (a: string): number };
 strOrNum = new unionWithRestParameter3("hello"); // error no call signature
 strOrNum = new unionWithRestParameter3("hello", 10); // error no call signature
 strOrNum = new unionWithRestParameter3("hello", 10, 11); // error no call signature
@@ -610,22 +596,19 @@ numOrDate = unionOfDifferentReturnType["hello"]; // number | Date
 numOrDate = unionOfDifferentReturnType[10]; // number | Date
 
 var unionOfTypesWithAndWithoutStringSignature:
-  | { [a: string]: number }
-  | boolean;
+  { [a: string]: number } | boolean;
 anyVar = unionOfTypesWithAndWithoutStringSignature["hello"]; // any
 anyVar = unionOfTypesWithAndWithoutStringSignature[10]; // any
 
 // If each type in U has a numeric index signature,
 // U has a numeric index signature of a union type of the types of the numeric index signatures from each type in U.
 var unionOfDifferentReturnType1:
-  | { [a: number]: number }
-  | { [a: number]: Date };
+  { [a: number]: number } | { [a: number]: Date };
 numOrDate = unionOfDifferentReturnType1["hello"]; // any
 numOrDate = unionOfDifferentReturnType1[10]; // number | Date
 
 var unionOfTypesWithAndWithoutStringSignature1:
-  | { [a: number]: number }
-  | boolean;
+  { [a: number]: number } | boolean;
 anyVar = unionOfTypesWithAndWithoutStringSignature1["hello"]; // any
 anyVar = unionOfTypesWithAndWithoutStringSignature1[10]; // any
 

tests/format/typescript/prettier-ignore/__snapshots__/format.test.js.snap

@@ -131,7 +131,8 @@ type c = {
 };
 
 type d = {
-  [A in B]: // prettier-ignore
+  [A in B]:
+    // prettier-ignore
     C | D;
 };
 
@@ -150,7 +151,8 @@ type f = {
 };
 
 type g = {
-  [A in B]: /* prettier-ignore */
+  [A in B]:
+    /* prettier-ignore */
     C | D;
 };
 

tests/format/typescript/property-signature/consistent-with-flow/__snapshots__/format.test.js.snap

@@ -66,7 +66,8 @@ export interface DirectiveArgumentNode extends ArrayExpression {
 
 =====================================output=====================================
 export interface DirectiveArgumentNode extends ArrayExpression {
-  elements: // dir, exp, arg, modifiers
+  elements:
+    // dir, exp, arg, modifiers
     | [string]
     | [string, ExpressionNode]
     | [string, ExpressionNode, ExpressionNode]

tests/format/typescript/type-parameters-arguments/__snapshots__/format.test.js.snap

@@ -62,7 +62,8 @@ type A<
 type BufferStreamOrVoid<
   C extends undefined | Buffer | Stream | boolean,
   P extends undefined | Buffer,
-  R extends Buffer | Stream | void = // Inline comment about void.
+  R extends
+    Buffer | Stream | void = // Inline comment about void.
     // Above line comment about exclue.
     Exclude<C, false> extends never
       ? void
@@ -556,13 +557,11 @@ export type OuterType32<
 
 export type OuterType4<
   LongerLongerLongerLongerInnerType extends
-    | LongerLongerLongerLongerLongerLo
-    | ngerLongerLongerOtherType,
+    LongerLongerLongerLongerLongerLo | ngerLongerLongerOtherType,
 > = { a: 1 };
 export type OuterType42<
   LongerLongerLongerLongerInnerType =
-    | LongerLongerLongerLongerLongerLo
-    | ngerLongerLongerOtherType,
+    LongerLongerLongerLongerLongerLo | ngerLongerLongerOtherType,
 > = { a: 1 };
 
 ================================================================================

tests/format/typescript/union/10599.ts

@@ -0,0 +1,16 @@
+export interface ProductStatus {
+  type:
+    // eslint-disable-next-line sonar/max-union-size
+    | 'NotDeployed'
+    | 'InDeployment'
+    | 'Running'
+    | 'DeploymentFailure'
+    | 'RunningAbnormal'
+    | 'Deleting'
+    | 'DeleteFailure'
+    | 'DeploymentSucceed'
+    | 'SystemError'
+    | 'Upgrading';
+  icon: string;
+  text: string;
+}

tests/format/typescript/union/5849.ts

@@ -0,0 +1,32 @@
+export type TransformedSource = {
+  code: string;
+  map?:
+    // copied from https://github.com/DefinitelyTyped/DefinitelyTyped/blob/363cdf403a74e0372e87bbcd15eb1668f4c5230b/types/babel__core/index.d.ts#L371-L379
+    | {
+        version: number;
+        sources: string[];
+        names: string[];
+        sourceRoot?: string;
+        sourcesContent?: string[];
+        mappings: string;
+        file: string;
+      }
+    | string
+    | null;
+};
+
+export type TransformedSource2 = {
+  code: string,
+  map?: // copied from https://github.com/DefinitelyTyped/DefinitelyTyped/blob/363cdf403a74e0372e87bbcd15eb1668f4c5230b/types/babel__core/index.d.ts#L371-L379
+  | {
+        version: number,
+        sources: string[],
+        names: string[],
+        sourceRoot?: string,
+        sourcesContent?: string[],
+        mappings: string,
+        file: string
+      }
+    | string
+    | null
+};

tests/format/typescript/union/7725.ts

@@ -0,0 +1,16 @@
+type T = {
+  prop:
+    // comment
+    | T1
+    // comment
+    | T2
+    // comment
+}
+
+type T2 = (arg:
+  // comment
+  | T1
+  // comment
+  | T2
+  // comment
+) => void

tests/format/typescript/union/__snapshots__/format.test.js.snap

@@ -1,5 +1,168 @@
 // Jest Snapshot v1, https://jestjs.io/docs/snapshot-testing
 
+exports[`5849.ts format 1`] = `
+====================================options=====================================
+parsers: ["typescript"]
+                                                      printWidth: 80 (default) |
+=====================================input======================================
+export type TransformedSource = {
+  code: string;
+  map?:
+    // copied from https://github.com/DefinitelyTyped/DefinitelyTyped/blob/363cdf403a74e0372e87bbcd15eb1668f4c5230b/types/babel__core/index.d.ts#L371-L379
+    | {
+        version: number;
+        sources: string[];
+        names: string[];
+        sourceRoot?: string;
+        sourcesContent?: string[];
+        mappings: string;
+        file: string;
+      }
+    | string
+    | null;
+};
+
+export type TransformedSource2 = {
+  code: string,
+  map?: // copied from https://github.com/DefinitelyTyped/DefinitelyTyped/blob/363cdf403a74e0372e87bbcd15eb1668f4c5230b/types/babel__core/index.d.ts#L371-L379
+  | {
+        version: number,
+        sources: string[],
+        names: string[],
+        sourceRoot?: string,
+        sourcesContent?: string[],
+        mappings: string,
+        file: string
+      }
+    | string
+    | null
+};
+
+=====================================output=====================================
+export type TransformedSource = {
+  code: string;
+  map?:
+    // copied from https://github.com/DefinitelyTyped/DefinitelyTyped/blob/363cdf403a74e0372e87bbcd15eb1668f4c5230b/types/babel__core/index.d.ts#L371-L379
+    | {
+        version: number;
+        sources: string[];
+        names: string[];
+        sourceRoot?: string;
+        sourcesContent?: string[];
+        mappings: string;
+        file: string;
+      }
+    | string
+    | null;
+};
+
+export type TransformedSource2 = {
+  code: string;
+  map?:
+    // copied from https://github.com/DefinitelyTyped/DefinitelyTyped/blob/363cdf403a74e0372e87bbcd15eb1668f4c5230b/types/babel__core/index.d.ts#L371-L379
+    | {
+        version: number;
+        sources: string[];
+        names: string[];
+        sourceRoot?: string;
+        sourcesContent?: string[];
+        mappings: string;
+        file: string;
+      }
+    | string
+    | null;
+};
+
+================================================================================
+`;
+
+exports[`7725.ts format 1`] = `
+====================================options=====================================
+parsers: ["typescript"]
+                                                      printWidth: 80 (default) |
+=====================================input======================================
+type T = {
+  prop:
+    // comment
+    | T1
+    // comment
+    | T2
+    // comment
+}
+
+type T2 = (arg:
+  // comment
+  | T1
+  // comment
+  | T2
+  // comment
+) => void
+
+=====================================output=====================================
+type T = {
+  prop:
+    // comment
+    | T1
+    // comment
+    | T2;
+  // comment
+};
+
+type T2 = (
+  arg:
+    // comment
+    | T1
+    // comment
+    | T2,
+  // comment
+) => void;
+
+================================================================================
+`;
+
+exports[`10599.ts format 1`] = `
+====================================options=====================================
+parsers: ["typescript"]
+                                                      printWidth: 80 (default) |
+=====================================input======================================
+export interface ProductStatus {
+  type:
+    // eslint-disable-next-line sonar/max-union-size
+    | 'NotDeployed'
+    | 'InDeployment'
+    | 'Running'
+    | 'DeploymentFailure'
+    | 'RunningAbnormal'
+    | 'Deleting'
+    | 'DeleteFailure'
+    | 'DeploymentSucceed'
+    | 'SystemError'
+    | 'Upgrading';
+  icon: string;
+  text: string;
+}
+
+=====================================output=====================================
+export interface ProductStatus {
+  type:
+    // eslint-disable-next-line sonar/max-union-size
+    | "NotDeployed"
+    | "InDeployment"
+    | "Running"
+    | "DeploymentFailure"
+    | "RunningAbnormal"
+    | "Deleting"
+    | "DeleteFailure"
+    | "DeploymentSucceed"
+    | "SystemError"
+    | "Upgrading";
+  icon: string;
+  text: string;
+}
+
+================================================================================
+`;
+
 exports[`inlining.ts format 1`] = `
 ====================================options=====================================
 parsers: ["typescript"]
@@ -149,6 +312,32 @@ type T8 = number | ((arg: any) => void);
 ================================================================================
 `;
 
+exports[`trailing-comment.ts format 1`] = `
+====================================options=====================================
+parsers: ["typescript"]
+                                                      printWidth: 80 (default) |
+=====================================input======================================
+export const CONDITIONAL_AXIS_PROP_INDEX: Record<
+  ConditionalAxisProp,
+  {
+    part: keyof AxisEncode;
+    vgProp: VgEncodeChannel;
+  } | null // null if we need to convert condition to signal
+> = {
+}
+
+=====================================output=====================================
+export const CONDITIONAL_AXIS_PROP_INDEX: Record<
+  ConditionalAxisProp,
+  {
+    part: keyof AxisEncode;
+    vgProp: VgEncodeChannel;
+  } | null // null if we need to convert condition to signal
+> = {};
+
+================================================================================
+`;
+
 exports[`union-parens.ts format 1`] = `
 ====================================options=====================================
 parsers: ["typescript"]
@@ -306,8 +495,7 @@ type State = {
 );
 
 const foo1 = [abc, def, ghi, jkl, mno, pqr, stu, vwx, yz] as (
-  | string
-  | undefined
+  string | undefined
 )[];
 
 const foo2: (

tests/format/typescript/union/comments/__snapshots__/format.test.js.snap

@@ -50,7 +50,8 @@ type A3 = /* block comment
 
 =====================================output=====================================
 export interface DirectiveArgumentNode1 extends ArrayExpression {
-  elements: // dir, exp, arg, modifiers
+  elements:
+    // dir, exp, arg, modifiers
     | [string]
     | [string, ExpressionNode]
     | [string, ExpressionNode, ExpressionNode]
@@ -58,7 +59,8 @@ export interface DirectiveArgumentNode1 extends ArrayExpression {
 }
 
 export class DirectiveArgumentNode12 extends ArrayExpression {
-  elements: // dir, exp, arg, modifiers
+  elements:
+    // dir, exp, arg, modifiers
     | [string]
     | [string, ExpressionNode]
     | [string, ExpressionNode, ExpressionNode]
@@ -71,7 +73,8 @@ type A = // dir, exp, arg, modifiers
   | [string, ExpressionNode, ExpressionNode]
   | [string, ExpressionNode, ExpressionNode, ObjectExpression];
 
-const elements: // dir, exp, arg, modifiers
+const elements:
+  // dir, exp, arg, modifiers
   | [string]
   | [string, ExpressionNode]
   | [string, ExpressionNode, ExpressionNode]
@@ -214,3 +217,24 @@ type A4 =
 
 ================================================================================
 `;
+
+exports[`mutiple.ts format 1`] = `
+====================================options=====================================
+parsers: ["typescript", "flow"]
+                                                      printWidth: 80 (default) |
+=====================================input======================================
+type _Test =
+  // forcing the test onto a new line so it isn't covered by the expect error
+  // If there are any enum members that don't have a corresponding TSESTree.Node, then this line will error with "Type 'string | number | symbol' is not assignable to type 'string'."
+  // eslint-disable-next-line @typescript-eslint/no-invalid-void-type
+  TakesString<AllKeys> | void;
+
+=====================================output=====================================
+type _Test =
+  // forcing the test onto a new line so it isn't covered by the expect error
+  // If there are any enum members that don't have a corresponding TSESTree.Node, then this line will error with "Type 'string | number | symbol' is not assignable to type 'string'."
+  // eslint-disable-next-line @typescript-eslint/no-invalid-void-type
+  TakesString<AllKeys> | void;
+
+================================================================================
+`;

tests/format/typescript/union/comments/mutiple.ts

@@ -0,0 +1,5 @@
+type _Test =
+  // forcing the test onto a new line so it isn't covered by the expect error
+  // If there are any enum members that don't have a corresponding TSESTree.Node, then this line will error with "Type 'string | number | symbol' is not assignable to type 'string'."
+  // eslint-disable-next-line @typescript-eslint/no-invalid-void-type
+  TakesString<AllKeys> | void;

tests/format/typescript/union/consistent-with-flow/18647.ts

@@ -0,0 +1,18 @@
+type T = any extends B
+  /**
+  * Comment
+  */
+    ? B | C
+    : D;
+type T2 = any extends B
+    ? B | C
+  /**
+  * Comment
+  */
+    : D;
+T = any instanceof B
+  /**
+  * Comment
+  */
+    ? B | C
+    : D;

tests/format/typescript/union/consistent-with-flow/18819.ts

@@ -0,0 +1,3 @@
+functionArg = a as
+  // comment
+  TSESTree.ArrowFunctionExpression | TSESTree.ArrowFunctionExpression | TSESTree.FunctionExpression | undefined;

tests/format/typescript/union/consistent-with-flow/__snapshots__/format.test.js.snap

@@ -60,42 +60,96 @@ type ClassLike________80 =
 
 =====================================output=====================================
 export type ButtonColor =
-  | "primary"
-  | "danger"
-  | "warning"
-  | "muted"
-  | "success";
+  "primary" | "danger" | "warning" | "muted" | "success";
 export type Button__80 = "primary" | "danger" | "warning" | "muted" | "success";
 
 export type SupportOptionType =
-  | "int"
-  | "string"
-  | "boolean"
-  | "choice"
-  | "path";
+  "int" | "string" | "boolean" | "choice" | "path";
 export type SupportOption_80 = "int" | "string" | "boolean" | "choice" | "path";
 
 export type RenderContextType =
-  | "data"
-  | "header"
-  | "footer"
-  | "columnsSelector";
+  "data" | "header" | "footer" | "columnsSelector";
 export type RenderContext_80 = "data" | "header" | "footer" | "columnsSelector";
 
 export type PropertyNameNonComputed =
-  | Identifier
-  | NumberLiteral
-  | StringLiteral;
+  Identifier | NumberLiteral | StringLiteral;
 export type PropertyNameNon_____80 = Identifier | NumberLiteral | StringLiteral;
 
 type ClassLikeDeclaration =
-  | TSESTree.ClassDeclaration
-  | TSESTree.ClassExpression;
+  TSESTree.ClassDeclaration | TSESTree.ClassExpression;
 type ClassLike________80 = TSESTree.ClassDeclaration | TSESTree.ClassExpression;
 
 ================================================================================
 `;
 
+exports[`18647.ts format 1`] = `
+====================================options=====================================
+parsers: ["typescript", "flow"]
+                                                      printWidth: 80 (default) |
+=====================================input======================================
+type T = any extends B
+  /**
+  * Comment
+  */
+    ? B | C
+    : D;
+type T2 = any extends B
+    ? B | C
+  /**
+  * Comment
+  */
+    : D;
+T = any instanceof B
+  /**
+  * Comment
+  */
+    ? B | C
+    : D;
+
+=====================================output=====================================
+type T = any extends B
+  ? /**
+     * Comment
+     */
+    B | C
+  : D;
+type T2 = any extends B
+  ? B | C
+  : /**
+     * Comment
+     */
+    D;
+T =
+  any instanceof B
+    ? /**
+       * Comment
+       */
+      B | C
+    : D;
+
+================================================================================
+`;
+
+exports[`18819.ts format 1`] = `
+====================================options=====================================
+parsers: ["typescript", "flow"]
+                                                      printWidth: 80 (default) |
+=====================================input======================================
+functionArg = a as
+  // comment
+  TSESTree.ArrowFunctionExpression | TSESTree.ArrowFunctionExpression | TSESTree.FunctionExpression | undefined;
+
+=====================================output=====================================
+functionArg = a as
+  // comment
+  | TSESTree.ArrowFunctionExpression
+  | TSESTree.ArrowFunctionExpression
+  | TSESTree.FunctionExpression
+  | undefined;
+
+================================================================================
+`;
+
 exports[`comment.ts format 1`] = `
 ====================================options=====================================
 parsers: ["typescript", "flow"]
@@ -183,6 +237,26 @@ type B3 = a | /* 1 */ /* 2 */ b;
 ================================================================================
 `;
 
+exports[`conditional.ts format 1`] = `
+====================================options=====================================
+parsers: ["typescript", "flow"]
+                                                      printWidth: 80 (default) |
+=====================================input======================================
+// https://github.com/excalidraw/excalidraw/blob/f12ae80ba1e1364952c6c6c440ac4212acd06eab/packages/excalidraw/tests/helpers/api.ts#L208C1-L210C15
+type A = T extends "arrow"
+    ? ExcalidrawArrowElement["startBinding"] | ExcalidrawElbowArrowElement["startBinding"]
+    : never;
+
+=====================================output=====================================
+// https://github.com/excalidraw/excalidraw/blob/f12ae80ba1e1364952c6c6c440ac4212acd06eab/packages/excalidraw/tests/helpers/api.ts#L208C1-L210C15
+type A = T extends "arrow"
+  ? | ExcalidrawArrowElement["startBinding"]
+    | ExcalidrawElbowArrowElement["startBinding"]
+  : never;
+
+================================================================================
+`;
+
 exports[`prettier-ignore.ts format 1`] = `
 ====================================options=====================================
 parsers: ["typescript", "flow"]
@@ -358,8 +432,8 @@ type A5 =
   | ({ key: string } | { key: string } | { key: string } | { key: string })
   | { key: string }
   | { key: string };
-type A6 = /*1*/
-  | A
+type A6 =
+  /*1*/ | A
   // A comment to force break
   | B;
 

tests/format/typescript/union/consistent-with-flow/conditional.ts

@@ -0,0 +1,4 @@
+// https://github.com/excalidraw/excalidraw/blob/f12ae80ba1e1364952c6c6c440ac4212acd06eab/packages/excalidraw/tests/helpers/api.ts#L208C1-L210C15
+type A = T extends "arrow"
+    ? ExcalidrawArrowElement["startBinding"] | ExcalidrawElbowArrowElement["startBinding"]
+    : never;

tests/format/typescript/union/trailing-comment.ts

@@ -0,0 +1,8 @@
+export const CONDITIONAL_AXIS_PROP_INDEX: Record<
+  ConditionalAxisProp,
+  {
+    part: keyof AxisEncode;
+    vgProp: VgEncodeChannel;
+  } | null // null if we need to convert condition to signal
+> = {
+}