Minor refactor to flow printer (#14002)

Co-authored-by: Sosuke Suzuki <aosukeke@gmail.com>

src/language-js/print/class.js

@@ -21,11 +21,20 @@ import { printPropertyKey } from "./property.js";
 import { printAssignment } from "./assignment.js";
 import { printClassMemberDecorators } from "./decorators.js";
 
+/*
+- `ClassDeclaration`
+- `ClassExpression`
+- `DeclareClass`(flow)
+*/
 function printClass(path, options, print) {
   const { node } = path;
   const parts = [];
 
-  if (node.declare) {
+  if (
+    node.declare ||
+    (node.type === "DeclareClass" &&
+      path.parent.type !== "DeclareExportDeclaration")
+  ) {
     parts.push("declare ");
   }
 

src/language-js/print/flow.js

@@ -5,7 +5,6 @@ import { printString, printNumber } from "../../common/util.js";
 import { replaceEndOfLine } from "../../document/utils.js";
 import UnexpectedNodeError from "../../utils/unexpected-node-error.js";
 import {
-  getParentExportDeclaration,
   isFunctionNotation,
   isGetterOrSetter,
   rawText,
@@ -36,61 +35,42 @@ import {
 function printFlow(path, options, print) {
   const { node } = path;
   const semi = options.semi ? ";" : "";
-  /** @type{Doc[]} */
-  const parts = [];
+
   switch (node.type) {
     case "DeclareClass":
-      return printFlowDeclaration(path, printClass(path, options, print));
+      return printClass(path, options, print);
     case "DeclareFunction":
-      return printFlowDeclaration(path, [
+      return [
+        path.parent.type !== "DeclareExportDeclaration" ? "declare " : "",
         "function ",
         print("id"),
         node.predicate ? " " : "",
         print("predicate"),
         semi,
-      ]);
+      ];
     case "DeclareModule":
-      return printFlowDeclaration(path, [
-        "module ",
-        print("id"),
-        " ",
-        print("body"),
-      ]);
+      return ["declare module ", print("id"), " ", print("body")];
     case "DeclareModuleExports":
-      return printFlowDeclaration(path, [
-        "module.exports",
-        ": ",
-        print("typeAnnotation"),
-        semi,
-      ]);
+      return ["declare module.exports", ": ", print("typeAnnotation"), semi];
     case "DeclareVariable":
-      return printFlowDeclaration(path, ["var ", print("id"), semi]);
-    case "DeclareInterface":
-      return printFlowDeclaration(path, printInterface(path, options, print));
+      return [
+        path.parent.type !== "DeclareExportDeclaration" ? "declare " : "",
+        "var ",
+        print("id"),
+        semi,
+      ];
     case "DeclareExportDeclaration":
-      return printFlowDeclaration(
-        path,
-        printExportDeclaration(path, options, print)
-      );
+      return printExportDeclaration(path, options, print);
     case "DeclareExportAllDeclaration":
-      return printFlowDeclaration(
-        path,
-        printExportAllDeclaration(path, options, print)
-      );
+      return printExportAllDeclaration(path, options, print);
     case "DeclareOpaqueType":
-    case "OpaqueType": {
-      const doc = printOpaqueType(path, options, print);
-      return node.type === "DeclareOpaqueType"
-        ? printFlowDeclaration(path, doc)
-        : doc;
-    }
+    case "OpaqueType":
+      return printOpaqueType(path, options, print);
+
     case "DeclareTypeAlias":
-    case "TypeAlias": {
-      const doc = printTypeAlias(path, options, print);
-      return node.type === "DeclareTypeAlias"
-        ? printFlowDeclaration(path, doc)
-        : doc;
-    }
+    case "TypeAlias":
+      return printTypeAlias(path, options, print);
+
     case "IntersectionTypeAnnotation":
       return printIntersectionType(path, options, print);
     case "UnionTypeAnnotation":
@@ -126,18 +106,24 @@ function printFlow(path, options, print) {
     case "BooleanLiteralTypeAnnotation":
       return String(node.value);
     case "DeclareEnum":
-    case "EnumDeclaration": {
-      const doc = ["enum ", print("id"), " ", print("body")];
-      return node.type === "DeclareEnum"
-        ? printFlowDeclaration(path, doc)
-        : doc;
-    }
+    case "EnumDeclaration":
+      return [
+        node.type === "DeclareEnum" &&
+        path.parent.type !== "DeclareExportDeclaration"
+          ? "declare "
+          : "",
+        "enum ",
+        print("id"),
+        " ",
+        print("body"),
+      ];
+
     case "EnumBooleanBody":
     case "EnumNumberBody":
     case "EnumStringBody":
-    case "EnumSymbolBody":
+    case "EnumSymbolBody": {
+      let type;
       if (node.type === "EnumSymbolBody" || node.explicitType) {
-        let type = null;
         switch (node.type) {
           case "EnumBooleanBody":
             type = "boolean";
@@ -152,10 +138,12 @@ function printFlow(path, options, print) {
             type = "symbol";
             break;
         }
-        parts.push("of ", type, " ");
       }
-      parts.push(printEnumMembers(path, print, options));
-      return parts;
+      return [
+        type ? `of ${type} ` : "",
+        printEnumMembers(path, print, options),
+      ];
+    }
 
     case "EnumBooleanMember":
     case "EnumNumberMember":
@@ -177,6 +165,7 @@ function printFlow(path, options, print) {
       ];
     }
 
+    case "DeclareInterface":
     case "InterfaceDeclaration":
     case "InterfaceTypeAnnotation":
       return printInterface(path, options, print);
@@ -191,13 +180,8 @@ function printFlow(path, options, print) {
       return kind === "plus" ? "+" : "-";
     }
     case "ObjectTypeCallProperty":
-      if (node.static) {
-        parts.push("static ");
-      }
+      return [node.static ? "static " : "", print("value")];
 
-      parts.push(print("value"));
-
-      return parts;
     case "ObjectTypeIndexer":
       return [
         node.static ? "static " : "",
@@ -308,18 +292,4 @@ function printFlow(path, options, print) {
   }
 }
 
-function printFlowDeclaration(path, printed) {
-  const parentExportDecl = getParentExportDeclaration(path);
-
-  if (parentExportDecl) {
-    assert.strictEqual(parentExportDecl.type, "DeclareExportDeclaration");
-    return printed;
-  }
-
-  // If the parent node has type DeclareExportDeclaration, then it
-  // will be responsible for printing the "declare" token. Otherwise
-  // it needs to be printed with this non-exported declaration node.
-  return ["declare ", printed];
-}
-
 export { printFlow };

src/language-js/print/interface.js

@@ -4,10 +4,16 @@ import { hasComment, identity, CommentCheckFlags } from "../utils/index.js";
 import { getTypeParametersGroupId } from "./type-parameters.js";
 import { printTypeScriptModifiers } from "./misc.js";
 
+/*
+- `TSInterfaceDeclaration`(TypeScript)
+- `DeclareInterface`(flow)
+- `InterfaceDeclaration`(flow)
+- `InterfaceTypeAnnotation`(flow)
+*/
 function printInterface(path, options, print) {
   const { node } = path;
   const parts = [];
-  if (node.declare) {
+  if (node.declare || node.type === "DeclareInterface") {
     parts.push("declare ");
   }
 

src/language-js/print/module.js

@@ -57,6 +57,11 @@ function printImportDeclaration(path, options, print) {
   return parts;
 }
 
+/*
+- `ExportDefaultDeclaration`
+- `ExportNamedDeclaration`
+- `DeclareExportDeclaration`(flow)
+*/
 function printExportDeclaration(path, options, print) {
   const { node } = path;
   /** @type{Doc[]} */
@@ -70,6 +75,10 @@ function printExportDeclaration(path, options, print) {
 
   const { type, exportKind, declaration } = node;
 
+  if (type === "DeclareExportDeclaration") {
+    parts.push("declare ");
+  }
+
   parts.push("export");
 
   const isDefaultExport = node.default || type === "ExportDefaultDeclaration";
@@ -106,13 +115,21 @@ function printExportDeclaration(path, options, print) {
   return parts;
 }
 
+/*
+- `ExportAllDeclaration`
+- `DeclareExportAllDeclaration`(flow)
+*/
 function printExportAllDeclaration(path, options, print) {
   const { node } = path;
   const semi = options.semi ? ";" : "";
   /** @type{Doc[]} */
   const parts = [];
 
-  const { exportKind, exported } = node;
+  const { exportKind, exported, type } = node;
+
+  if (type === "DeclareExportAllDeclaration") {
+    parts.push("declare ");
+  }
 
   parts.push("export");
 

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

@@ -56,10 +56,22 @@ function shouldHugType(node) {
   return false;
 }
 
+/*
+- `DeclareOpaqueType`(flow)
+- `OpaqueType`(flow)
+*/
 function printOpaqueType(path, options, print) {
   const semi = options.semi ? ";" : "";
   const { node } = path;
   const parts = [];
+
+  if (
+    node.type === "DeclareOpaqueType" &&
+    path.parent.type !== "DeclareExportDeclaration"
+  ) {
+    parts.push("declare ");
+  }
+
   parts.push("opaque type ", print("id"), print("typeParameters"));
 
   if (node.supertype) {
@@ -75,11 +87,21 @@ function printOpaqueType(path, options, print) {
   return parts;
 }
 
+/*
+- `DeclareTypeAlias`(flow)
+- `TypeAlias`(flow)
+- `TSTypeAliasDeclaration`(TypeScript)
+*/
 function printTypeAlias(path, options, print) {
   const semi = options.semi ? ";" : "";
   const { node } = path;
   const parts = [];
-  if (node.declare) {
+
+  if (
+    node.declare ||
+    (node.type === "DeclareTypeAlias" &&
+      path.parent.type !== "DeclareExportDeclaration")
+  ) {
     parts.push("declare ");
   }
   parts.push("type ", print("id"), print("typeParameters"));
@@ -284,7 +306,11 @@ function printFunctionType(path, options, print) {
   return group(parts);
 }
 
-// `TSIndexedAccessType`, `IndexedAccessType`, and `OptionalIndexedAccessType`
+/*
+- `TSIndexedAccessType`(TypeScript)
+- `IndexedAccessType`(flow)
+- `OptionalIndexedAccessType`(flow)
+*/
 function printIndexedAccessType(path, options, print) {
   const { node } = path;
   const leftDelimiter =

tests/format/misc/errors/flow/declare-export-interface/__snapshots__/jsfmt.spec.js.snap

@@ -0,0 +1,13 @@
+// Jest Snapshot v1, https://goo.gl/fbAQLP
+
+exports[`snippet: #0 [babel-flow] format 1`] = `
+"\`declare export interface\` is not supported. Use \`export interface\` instead. (1:16)
+> 1 | declare export interface A {}
+    |                ^"
+`;
+
+exports[`snippet: #0 [flow] format 1`] = `
+"\`declare export interface\` is not supported. Use \`export interface\` instead. (1:16)
+> 1 | declare export interface A {}
+    |                ^^^^^^^^^"
+`;

tests/format/misc/errors/flow/declare-export-interface/jsfmt.spec.js

@@ -0,0 +1,7 @@
+run_spec(
+  {
+    importMeta: import.meta,
+    snippets: ["declare export interface A {}"],
+  },
+  ["flow", "babel-flow"]
+);