Add parens to head of arrow function body instead of whole expression (…

…#14599)
prettier · Mar 29, 2023 · 3f1153b · 3f1153b
1 parent 9500403
commit 3f1153b
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Showing 9 changed files with 79 additions and 62 deletions.
diff --git a/changelog_unreleased/javascript/14599.md b/changelog_unreleased/javascript/14599.md
@@ -0,0 +1,13 @@
+#### Add parentheses to head of `ExpressionStatement` instead of the whole statement (#14599 by @fisker)
+
+<!-- prettier-ignore -->
+```jsx
+// Input
+const isArray = (object) => ({}).toString.call(foo) === "[object Array]";
+
+// Prettier stable
+const isArray = (object) => ({}.toString.call(foo) === "[object Array]");
+
+// Prettier main
+const isArray = (object) => ({}).toString.call(foo) === "[object Array]";
+```
diff --git a/src/language-js/needs-parens.js b/src/language-js/needs-parens.js
@@ -133,6 +133,23 @@ function needsParens(path, options) {
     }
   }
 
+  if (node.type === "ObjectExpression") {
+    const arrowFunctionBody = path.findAncestor(
+      (node) => node.type === "ArrowFunctionExpression"
+    )?.body;
+    if (
+      arrowFunctionBody &&
+      arrowFunctionBody.type !== "SequenceExpression" && // these have parens added anyway
+      arrowFunctionBody.type !== "AssignmentExpression" &&
+      startsWithNoLookaheadToken(
+        arrowFunctionBody,
+        (leftmostNode) => leftmostNode === node
+      )
+    ) {
+      return true;
+    }
+  }
+
   switch (parent.type) {
     case "ParenthesizedExpression":
       return false;
@@ -211,19 +228,6 @@ function needsParens(path, options) {
       }
       break;
 
-    case "ArrowFunctionExpression":
-      if (
-        key === "body" &&
-        node.type !== "SequenceExpression" && // these have parens added anyway
-        startsWithNoLookaheadToken(
-          node,
-          (node) => node.type === "ObjectExpression"
-        )
-      ) {
-        return true;
-      }
-      break;
-
     case "TypeAnnotation":
       if (
         path.match(

diff --git a/tests/format/js/arrows-bind/__snapshots__/jsfmt.spec.js.snap b/tests/format/js/arrows-bind/__snapshots__/jsfmt.spec.js.snap
@@ -38,7 +38,7 @@ a => ({}::b()\`\`[''].c++ && 0 ? 0 : 0);
 a::(b => c);
 
 =====================================output=====================================
-(a) => ({}::b()\`\`[""].c++ && 0 ? 0 : 0);
+(a) => ({})::b()\`\`[""].c++ && 0 ? 0 : 0;
 ((a) => b)::c;
 a::((b) => c);
 

diff --git a/tests/format/js/arrows/__snapshots__/jsfmt.spec.js.snap b/tests/format/js/arrows/__snapshots__/jsfmt.spec.js.snap
@@ -51,24 +51,24 @@ export default (() => {})();
 new (() => {})();
 if ((() => {}) ? 1 : 0) {
 }
-let f = () => ({}());
-let a = () => ({} instanceof a);
-a = () => ({} && a);
-a = () => ({}() && a);
-a = () => ({} && a && b);
-a = () => ({} + a);
-a = () => ({}()() && a);
-a = () => ({}.b && a);
-a = () => ({}[b] && a);
-a = () => ({}\`\` && a);
+let f = () => ({})();
+let a = () => ({}) instanceof a;
+a = () => ({}) && a;
+a = () => ({})() && a;
+a = () => ({}) && a && b;
+a = () => ({}) + a;
+a = () => ({})()() && a;
+a = () => ({}).b && a;
+a = () => ({})[b] && a;
+a = () => ({})\`\` && a;
 a = () => ({} = 0);
 a = () => ({}, a);
 (a) => a instanceof {};
-(a) => ({}().b && 0);
+(a) => ({})().b && 0;
 (a) => ({}().c = 0);
-(x) => ({}()());
-(x) => ({}()\`\`);
-(x) => ({}().b);
+(x) => ({})()();
+(x) => ({})()\`\`;
+(x) => ({})().b;
 a = (b) => c;
 (x) => (y = z);
 (x) => (y += z);
@@ -133,24 +133,24 @@ export default (() => {})();
 new (() => {})();
 if ((() => {}) ? 1 : 0) {
 }
-let f = () => ({}());
-let a = () => ({} instanceof a);
-a = () => ({} && a);
-a = () => ({}() && a);
-a = () => ({} && a && b);
-a = () => ({} + a);
-a = () => ({}()() && a);
-a = () => ({}.b && a);
-a = () => ({}[b] && a);
-a = () => ({}\`\` && a);
+let f = () => ({})();
+let a = () => ({}) instanceof a;
+a = () => ({}) && a;
+a = () => ({})() && a;
+a = () => ({}) && a && b;
+a = () => ({}) + a;
+a = () => ({})()() && a;
+a = () => ({}).b && a;
+a = () => ({})[b] && a;
+a = () => ({})\`\` && a;
 a = () => ({} = 0);
 a = () => ({}, a);
 a => a instanceof {};
-a => ({}().b && 0);
+a => ({})().b && 0;
 a => ({}().c = 0);
-x => ({}()());
-x => ({}()\`\`);
-x => ({}().b);
+x => ({})()();
+x => ({})()\`\`;
+x => ({})().b;
 a = b => c;
 x => (y = z);
 x => (y += z);

diff --git a/tests/format/js/objects/__snapshots__/jsfmt.spec.js.snap b/tests/format/js/objects/__snapshots__/jsfmt.spec.js.snap
@@ -166,9 +166,9 @@ const a3 = {
 };
 
 =====================================output=====================================
-() => ({}\`\`);
+() => ({})\`\`;
 ({})\`\`;
-a = () => ({}.x);
+a = () => ({}).x;
 ({}) && a, b;
 ({})::b, 0;
 ({})::b()\`\`[""].c++ && 0 ? 0 : 0, 0;

diff --git a/tests/format/js/optional-chaining/__snapshots__/jsfmt.spec.js.snap b/tests/format/js/optional-chaining/__snapshots__/jsfmt.spec.js.snap
@@ -159,19 +159,19 @@ a?.[b ? c : d];
   aaaaaaaaaaaaaaaaaaaaaaaa
 )?.();
 
-let f = () => ({}?.());
-let g = () => ({}?.b);
-a = () => ({}?.() && a);
-a = () => ({}?.()() && a);
-a = () => ({}?.().b && a);
-a = () => ({}?.b && a);
-a = () => ({}?.b() && a);
-(a) => ({}?.()?.b && 0);
-(a) => ({}?.b?.b && 0);
-(x) => ({}?.()());
-(x) => ({}?.().b);
-(x) => ({}?.b());
-(x) => ({}?.b.b);
+let f = () => ({})?.();
+let g = () => ({})?.b;
+a = () => ({})?.() && a;
+a = () => ({})?.()() && a;
+a = () => ({})?.().b && a;
+a = () => ({})?.b && a;
+a = () => ({})?.b() && a;
+(a) => ({})?.()?.b && 0;
+(a) => ({})?.b?.b && 0;
+(x) => ({})?.()();
+(x) => ({})?.().b;
+(x) => ({})?.b();
+(x) => ({})?.b.b;
 ({})?.a().b();
 ({ a: 1 })?.entries();
 

diff --git a/tests/format/typescript/as/__snapshots__/jsfmt.spec.js.snap b/tests/format/typescript/as/__snapshots__/jsfmt.spec.js.snap
@@ -89,7 +89,7 @@ async function g1() {
   const test = (await "foo") as number;
 }
 ({}) as X;
-() => ({} as X);
+() => ({}) as X;
 const state = JSON.stringify({
   next: window.location.href,
   nonce,

diff --git a/tests/format/typescript/non-null/__snapshots__/jsfmt.spec.js.snap b/tests/format/typescript/non-null/__snapshots__/jsfmt.spec.js.snap
@@ -27,9 +27,9 @@ const myFunction2 = (key: string): number =>
   ({
     a: 42,
     b: 42,
-  }[key]!);
+  })[key]!;
 
-const myFunction3 = (key) => ({}!.a);
+const myFunction3 = (key) => ({})!.a;
 
 const f = ((a) => {
   log(a);

diff --git a/tests/format/typescript/satisfies-operators/__snapshots__/jsfmt.spec.js.snap b/tests/format/typescript/satisfies-operators/__snapshots__/jsfmt.spec.js.snap
@@ -756,7 +756,7 @@ foo as unknown satisfies Bar;
 =====================================output=====================================
 ;({}) satisfies {}
 ;({}) satisfies X
-;() => ({} satisfies X)
+;() => ({}) satisfies X
 this.isTabActionBar((e.target || e.srcElement) satisfies HTMLElement)
 
 "current" in (props.pagination satisfies Object)
@@ -812,7 +812,7 @@ foo as unknown satisfies Bar;
 =====================================output=====================================
 ({}) satisfies {};
 ({}) satisfies X;
-() => ({} satisfies X);
+() => ({}) satisfies X;
 this.isTabActionBar((e.target || e.srcElement) satisfies HTMLElement);
 
 "current" in (props.pagination satisfies Object);