JavaScript: fix edge cases in type cast comment detection regex (#5793)

Fix edge cases involving {...} ([record @type](http://usejsdoc.org/tags-type.html)) and newlines in prettier's detection code for type cast comments

CHANGELOG.unreleased.md

@@ -67,3 +67,20 @@ Examples:
   <!-- Output (Prettier master) -->
   Prix·:·32·€
   ```
+
+- JavaScript: fix record type cast comment detection ([#5793] by [@yangsu])
+
+  Previously, type cast comments with record types were ignored and prettier
+  stripped the subsequent parens. Prettier master handles these cases correctly.
+
+  <!-- prettier-ignore -->
+  ```js
+  // Input
+  const v = /** @type {{key: number}} */ (value);
+
+  // Output (Prettier stable)
+  const v = /** @type {{key: number}} */ value;
+
+  // Output (Prettier master)
+  const v = /** @type {{key: number}} */ (value);
+  ```

src/language-js/needs-parens.js

@@ -34,11 +34,37 @@ function hasClosureCompilerTypeCastComment(text, path, locStart, locEnd) {
         comment =>
           comment.leading &&
           comments.isBlockComment(comment) &&
-          comment.value.match(/^\*\s*@type\s*{[^}]+}\s*$/) &&
+          isTypeCastComment(comment.value) &&
           util.getNextNonSpaceNonCommentCharacter(text, comment, locEnd) === "("
       )
     );
   }
+
+  function isTypeCastComment(comment) {
+    const trimmed = comment.trim();
+    if (!/^\*\s*@type\s*\{[^]+\}$/.test(trimmed)) {
+      return false;
+    }
+    let isCompletelyClosed = false;
+    let unpairedBracketCount = 0;
+    for (const char of trimmed) {
+      if (char === "{") {
+        if (isCompletelyClosed) {
+          return false;
+        }
+        unpairedBracketCount++;
+      } else if (char === "}") {
+        if (unpairedBracketCount === 0) {
+          return false;
+        }
+        unpairedBracketCount--;
+        if (unpairedBracketCount === 0) {
+          isCompletelyClosed = true;
+        }
+      }
+    }
+    return unpairedBracketCount === 0;
+  }
 }
 
 function needsParens(path, options) {

tests/comments/__snapshots__/jsfmt.spec.js.snap

@@ -350,6 +350,32 @@ var newArray = /** @type {array} */ (numberOrString).map(x => x);
 var newArray = /** @type {array} */ ((numberOrString)).map(x => x);
 var newArray = /** @type {array} */ ((numberOrString).map(x => x));
 
+
+const data = functionCall(
+  arg1,
+  arg2,
+  /** @type {{height: number, width: number}} */ (arg3));
+
+// Invalid type casts
+const v = /** @type {} */ (value);
+const v = /** @type {}} */ (value);
+const v = /** @type } */ (value);
+const v = /** @type { */ (value);
+const v = /** @type {{} */ (value);
+
+const style = /** @type {{
+  width: number,
+  height: number,
+  marginTop: number,
+  marginLeft: number,
+  marginRight: number,
+  marginBottom: number,
+}} */ ({
+  width,
+  height,
+  ...margins,
+});
+
 =====================================output=====================================
 // test to make sure comments are attached correctly
 let inlineComment = /* some comment */ someReallyLongFunctionCall(
@@ -374,6 +400,32 @@ var newArray = /** @type {array} */ (numberOrString).map(x => x);
 var newArray = /** @type {array} */ (numberOrString).map(x => x);
 var newArray = /** @type {array} */ (numberOrString.map(x => x));
 
+const data = functionCall(
+  arg1,
+  arg2,
+  /** @type {{height: number, width: number}} */ (arg3)
+);
+
+// Invalid type casts
+const v = /** @type {} */ value;
+const v = /** @type {}} */ value;
+const v = /** @type } */ value;
+const v = /** @type { */ value;
+const v = /** @type {{} */ value;
+
+const style = /** @type {{
+  width: number,
+  height: number,
+  marginTop: number,
+  marginLeft: number,
+  marginRight: number,
+  marginBottom: number,
+}} */ ({
+  width,
+  height,
+  ...margins
+});
+
 ================================================================================
 `;
 

tests/comments/closure-compiler-type-cast.js

@@ -18,3 +18,29 @@ function returnValue() {
 var newArray = /** @type {array} */ (numberOrString).map(x => x);
 var newArray = /** @type {array} */ ((numberOrString)).map(x => x);
 var newArray = /** @type {array} */ ((numberOrString).map(x => x));
+
+
+const data = functionCall(
+  arg1,
+  arg2,
+  /** @type {{height: number, width: number}} */ (arg3));
+
+// Invalid type casts
+const v = /** @type {} */ (value);
+const v = /** @type {}} */ (value);
+const v = /** @type } */ (value);
+const v = /** @type { */ (value);
+const v = /** @type {{} */ (value);
+
+const style = /** @type {{
+  width: number,
+  height: number,
+  marginTop: number,
+  marginLeft: number,
+  marginRight: number,
+  marginBottom: number,
+}} */ ({
+  width,
+  height,
+  ...margins,
+});