Fix missing parentheses around throw expression (#20028)

Co-authored-by: fisker <lionkay@gmail.com>

changelog_unreleased/javascript/20028.md

@@ -0,0 +1,13 @@
+#### Keep necessary parentheses around `throw` expression (#20028 by @lazerg)
+
+<!-- prettier-ignore -->
+```jsx
+// Input
+(throw error);
+
+// Prettier stable
+throw error;
+
+// Prettier main
+(throw error);
+```

src/language-js/parentheses/needs-parentheses.js

@@ -62,7 +62,8 @@ function needsParentheses(path, options) {
     node.type === "ObjectExpression" ||
     node.type === "FunctionExpression" ||
     node.type === "ClassExpression" ||
-    node.type === "DoExpression"
+    node.type === "DoExpression" ||
+    (node.type === "UnaryExpression" && node.operator === "throw")
   ) {
     const expression = path.findAncestor(
       (node) => node.type === "ExpressionStatement",

tests/format/js/do-expression/__snapshots__/format.test.js.snap

@@ -287,10 +287,6 @@ function foo() {
   );
 }
 
-(do {});
-(do {} + 1);
-(1 + do {});
-() => do {};
 
 (do {
   switch(0) {
@@ -358,11 +354,6 @@ function foo() {
   );
 }
 
-(do {});
-(do {}) + 1;
-1 + do {};
-() => do {};
-
 (do {
   switch (0) {
     case 0:

tests/format/js/do-expression/do-expression.js

@@ -34,10 +34,6 @@ function foo() {
   );
 }
 
-(do {});
-(do {} + 1);
-(1 + do {});
-() => do {};
 
 (do {
   switch(0) {

tests/format/js/parentheses/__snapshots__/format.test.js.snap

@@ -0,0 +1,216 @@
+// Jest Snapshot v1, https://jestjs.io/docs/snapshot-testing
+
+exports[`do-expression.js format 1`] = `
+====================================options=====================================
+parsers: ["babel", "flow", "typescript"]
+                                                      printWidth: 80 (default) |
+=====================================input======================================
+(do {});
+(async do {});
+(throw error);
+
+(do {}) || fallback;
+(async do {}) || fallback;
+(throw error) || fallback;
+
+(do {}).message;
+(async do {}).message;
+(throw error).message;
+
+// Head, bug
+((do {}), _);
+((async do {}), _);
+((throw error), _);
+// Tail
+(_, (do {}));
+(_, (async do {}));
+(_, (throw error));
+// Middle
+(
+  _,
+  (do {}),
+  (async do {}),
+  (throw error),
+  _
+);
+
+(do {}) + 1;
+(async do {}) + 1;
+(throw error) + 1;
+
+1 + do {};
+1 + async do {};
+1 + throw error;
+
+() => do {};
+() => async do {};
+() => throw error;
+
+if (condition) (do {});
+if (condition) (async do {});
+if (condition) (throw error);
+
+for (;;) (do {});
+for (;;) (async do {});
+for (;;) (throw error);
+
+label: (do {});
+label: (async do {});
+label: (throw error);
+
+value = do {};
+value = async do {};
+value = throw error;
+
+=====================================output=====================================
+(do {});
+(async do {});
+(throw error);
+
+(do {}) || fallback;
+(async do {}) || fallback;
+(throw error) || fallback;
+
+(do {}).message;
+(async do {}).message;
+(throw error).message;
+
+// Head, bug
+((do {}), _);
+((async do {}), _);
+((throw error), _);
+// Tail
+(_, do {});
+(_, async do {});
+(_, throw error);
+// Middle
+(_, do {}, async do {}, throw error, _);
+
+(do {}) + 1;
+(async do {}) + 1;
+(throw error) + 1;
+
+1 + do {};
+1 + async do {};
+1 + throw error;
+
+() => do {};
+() => async do {};
+() => throw error;
+
+if (condition) (do {});
+if (condition) (async do {});
+if (condition) (throw error);
+
+for (;;) (do {});
+for (;;) (async do {});
+for (;;) (throw error);
+
+label: (do {});
+label: (async do {});
+label: (throw error);
+
+value = do {};
+value = async do {};
+value = throw error;
+
+================================================================================
+`;
+
+exports[`do-expression.js format[acorn] 1`] = `
+"Unexpected token (1:2)
+> 1 | (do {});
+    |  ^
+  2 | (async do {});
+  3 | (throw error);
+  4 |
+Cause: Unexpected token (1:1)"
+`;
+
+exports[`do-expression.js format[espree] 1`] = `
+"Unexpected token do (1:2)
+> 1 | (do {});
+    |  ^
+  2 | (async do {});
+  3 | (throw error);
+  4 |
+Cause: Unexpected token do"
+`;
+
+exports[`do-expression.js format[flow] 1`] = `
+"Unexpected token \`do\` (1:2)
+> 1 | (do {});
+    |  ^
+  2 | (async do {});
+  3 | (throw error);
+  4 |
+Cause: Unexpected token \`do\` (1:1)"
+`;
+
+exports[`do-expression.js format[hermes] 1`] = `
+"invalid expression (1:2)
+> 1 | (do {});
+    |  ^
+  2 | (async do {});
+  3 | (throw error);
+  4 |
+Cause: invalid expression (1:1)
+(do {});
+ ^"
+`;
+
+exports[`do-expression.js format[meriyah] 1`] = `
+"Unexpected token: 'do' (1:2)
+> 1 | (do {});
+    |  ^^
+  2 | (async do {});
+  3 | (throw error);
+  4 |
+Cause: [1:1-1:3]: Unexpected token: 'do'"
+`;
+
+exports[`do-expression.js format[oxc] 1`] = `
+"Unexpected token (1:2)
+> 1 | (do {});
+    |  ^^
+  2 | (async do {});
+  3 | (throw error);
+  4 |"
+`;
+
+exports[`do-expression.js format[oxc-ts] 1`] = `
+"Unexpected token (1:2)
+> 1 | (do {});
+    |  ^^
+  2 | (async do {});
+  3 | (throw error);
+  4 |"
+`;
+
+exports[`do-expression.js format[typescript] 1`] = `
+"Expression expected. (1:2)
+> 1 | (do {});
+    |  ^
+  2 | (async do {});
+  3 | (throw error);
+  4 |
+Cause: Expression expected."
+`;
+
+exports[`do-expression.js format[yuku] 1`] = `
+"'do' is reserved and cannot be used as an identifier (1:2)
+> 1 | (do {});
+    |  ^^
+  2 | (async do {});
+  3 | (throw error);
+  4 |"
+`;
+
+exports[`do-expression.js format[yuku-ts] 1`] = `
+"'do' is reserved and cannot be used as an identifier (1:2)
+> 1 | (do {});
+    |  ^^
+  2 | (async do {});
+  3 | (throw error);
+  4 |"
+`;

tests/format/js/parentheses/do-expression.js

@@ -0,0 +1,56 @@
+(do {});
+(async do {});
+(throw error);
+
+(do {}) || fallback;
+(async do {}) || fallback;
+(throw error) || fallback;
+
+(do {}).message;
+(async do {}).message;
+(throw error).message;
+
+// Head, bug
+((do {}), _);
+((async do {}), _);
+((throw error), _);
+// Tail
+(_, (do {}));
+(_, (async do {}));
+(_, (throw error));
+// Middle
+(
+  _,
+  (do {}),
+  (async do {}),
+  (throw error),
+  _
+);
+
+(do {}) + 1;
+(async do {}) + 1;
+(throw error) + 1;
+
+1 + do {};
+1 + async do {};
+1 + throw error;
+
+() => do {};
+() => async do {};
+() => throw error;
+
+if (condition) (do {});
+if (condition) (async do {});
+if (condition) (throw error);
+
+for (;;) (do {});
+for (;;) (async do {});
+for (;;) (throw error);
+
+label: (do {});
+label: (async do {});
+label: (throw error);
+
+value = do {};
+value = async do {};
+value = throw error;

tests/format/js/parentheses/format.test.js

@@ -0,0 +1,14 @@
+runFormatTest(import.meta, ["babel", "flow", "typescript"], {
+  errors: {
+    acorn: ["do-expression.js"],
+    espree: ["do-expression.js"],
+    meriyah: ["do-expression.js"],
+    oxc: ["do-expression.js"],
+    "oxc-ts": ["do-expression.js"],
+    yuku: ["do-expression.js"],
+    "yuku-ts": ["do-expression.js"],
+    typescript: ["do-expression.js"],
+    flow: ["do-expression.js"],
+    hermes: ["do-expression.js"],
+  },
+});