Don't treat Flow inexact tuples as empty (#18616)

changelog_unreleased/flow/18616.md

@@ -0,0 +1,23 @@
+#### Improve comment format in inexact tuples (#18616 by @fisker)
+
+<!-- prettier-ignore -->
+```jsx
+// Input
+type A = [// comment
+...];
+type B = [/* comment */...];
+
+// Prettier stable
+type A = [...
+  // comment
+];
+type B = [...
+  /* comment */
+];
+
+// Prettier main
+type A = [
+  ...// comment
+];
+type B = [.../* comment */];
+```

src/language-js/print/array.js

@@ -30,13 +30,11 @@ import { printTypeAnnotationProperty } from "./type-annotation.js";
 
 function printEmptyArrayElements(path, options, openBracket, closeBracket) {
   const { node } = path;
-  const inexact = node.inexact ? "..." : "";
   if (!hasComment(node, CommentCheckFlags.Dangling)) {
-    return [openBracket, inexact, closeBracket];
+    return [openBracket, closeBracket];
   }
   return group([
     openBracket,
-    inexact,
     printDanglingComments(path, options, { indent: true }),
     softline,
     closeBracket,
@@ -58,7 +56,7 @@ function printArray(path, options, print) {
   const closeBracket = "]";
   const elementsProperty = isTupleType(node) ? "elementTypes" : "elements";
   const elements = node[elementsProperty];
-  if (elements.length === 0) {
+  if (elements.length === 0 && !node.inexact) {
     parts.push(
       printEmptyArrayElements(path, options, openBracket, closeBracket),
     );
@@ -82,23 +80,26 @@ function printArray(path, options, print) {
     const groupId = Symbol("array");
 
     const shouldBreak =
-      !options.__inJestEach &&
-      elements.length > 1 &&
-      elements.every((element, i, elements) => {
-        const elementType = element?.type;
-        if (!isArrayExpression(element) && !isObjectExpression(element)) {
-          return false;
-        }
+      (!options.__inJestEach &&
+        elements.length > 1 &&
+        elements.every((element, i, elements) => {
+          const elementType = element?.type;
+          if (!isArrayExpression(element) && !isObjectExpression(element)) {
+            return false;
+          }
 
-        const nextElement = elements[i + 1];
-        if (nextElement && elementType !== nextElement.type) {
-          return false;
-        }
+          const nextElement = elements[i + 1];
+          if (nextElement && elementType !== nextElement.type) {
+            return false;
+          }
 
-        const itemsKey = isArrayExpression(element) ? "elements" : "properties";
+          const itemsKey = isArrayExpression(element)
+            ? "elements"
+            : "properties";
 
-        return element[itemsKey] && element[itemsKey].length > 1;
-      });
+          return element[itemsKey] && element[itemsKey].length > 1;
+        })) ||
+      hasComment(node, CommentCheckFlags.Dangling | CommentCheckFlags.Line);
 
     const shouldUseConciseFormatting = isConciselyPrintedArray(node, options);
 

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

@@ -1,5 +1,63 @@
 // Jest Snapshot v1, https://jestjs.io/docs/snapshot-testing
 
+exports[`comments.js format 1`] = `
+====================================options=====================================
+parsers: ["flow"]
+printWidth: 80
+                                                                                | printWidth
+=====================================input======================================
+type Empty11 = [
+// 11
+...];
+type Empty12 = [// 12
+...];
+type Empty13 = [
+...// 13
+];
+type Empty14 = [
+...
+// 14
+];
+
+type Empty21 = [
+/* 21 */
+...];
+type Empty22 = [/* 22 */
+...];
+type Empty23 = [
+.../* 23 */
+];
+type Empty24 = [
+...
+/* 24 */
+];
+type Empty25 = [/* 25 */...];
+type Empty26 = [.../* 25 */];
+
+=====================================output=====================================
+type Empty11 = [
+  ...// 11
+];
+type Empty12 = [
+  ...// 12
+];
+type Empty13 = [
+  ...// 13
+];
+type Empty14 = [
+  ...// 14
+];
+
+type Empty21 = [.../* 21 */];
+type Empty22 = [.../* 22 */];
+type Empty23 = [.../* 23 */];
+type Empty24 = [.../* 24 */];
+type Empty25 = [.../* 25 */];
+type Empty26 = [.../* 25 */];
+
+================================================================================
+`;
+
 exports[`inexact.js format 1`] = `
 ====================================options=====================================
 parsers: ["flow"]

tests/format/flow/tuples/comments.js

@@ -0,0 +1,27 @@
+type Empty11 = [
+// 11
+...];
+type Empty12 = [// 12
+...];
+type Empty13 = [
+...// 13
+];
+type Empty14 = [
+...
+// 14
+];
+
+type Empty21 = [
+/* 21 */
+...];
+type Empty22 = [/* 22 */
+...];
+type Empty23 = [
+.../* 23 */
+];
+type Empty24 = [
+...
+/* 24 */
+];
+type Empty25 = [/* 25 */...];
+type Empty26 = [.../* 25 */];