feat: allowVoid option in array-callback-return (#17564)

* feat: allowVoid option in array-callback-return Refs #17285 * feat: refactor code and add docs * feat: allow void in return-statement * feat: add more tests for allowVoid
eslint · Sep 17, 2023 · 85a3d9e · 85a3d9e
1 parent bd7a71f
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diff --git a/docs/src/rules/array-callback-return.md b/docs/src/rules/array-callback-return.md
@@ -92,10 +92,13 @@ var bar = foo.map(node => node.getAttribute("id"));
 
 ## Options
 
-This rule accepts a configuration object with two options:
+This rule accepts a configuration object with three options:
 
 * `"allowImplicit": false` (default) When set to `true`, allows callbacks of methods that require a return value to implicitly return `undefined` with a `return` statement containing no expression.
 * `"checkForEach": false` (default) When set to `true`, rule will also report `forEach` callbacks that return a value.
+* `"allowVoid": false` (default) When set to `true`, allows `void` in `forEach` callbacks, so rule will not report the return value with a `void` operator.
+
+**Note:** `{ "allowVoid": true }` works only if `checkForEach` option is set to `true`.  
 
 ### allowImplicit
 
@@ -122,7 +125,7 @@ Examples of **incorrect** code for the `{ "checkForEach": true }` option:
 /*eslint array-callback-return: ["error", { checkForEach: true }]*/
 
 myArray.forEach(function(item) {
-    return handleItem(item)
+    return handleItem(item);
 });
 
 myArray.forEach(function(item) {
@@ -132,11 +135,24 @@ myArray.forEach(function(item) {
     handleItem(item);
 });
 
+myArray.forEach(function(item) {
+    if (item < 0) {
+        return void x;
+    }
+    handleItem(item);
+});
+
 myArray.forEach(item => handleItem(item));
 
+myArray.forEach(item => void handleItem(item));
+
 myArray.forEach(item => {
     return handleItem(item);
 });
+
+myArray.forEach(item => {
+    return void handleItem(item);
+});
 ```
 
 :::
@@ -171,6 +187,31 @@ myArray.forEach(item => {
 
 :::
 
+### allowVoid
+
+Examples of **correct** code for the `{ "allowVoid": true }` option:
+
+:::correct
+
+```js
+/*eslint array-callback-return: ["error", { checkForEach: true, allowVoid: true }]*/
+
+myArray.forEach(item => void handleItem(item));
+
+myArray.forEach(item => {
+    return void handleItem(item);
+});
+
+myArray.forEach(item => {
+    if (item < 0) {
+        return void x;
+    }
+    handleItem(item);
+});
+```
+
+:::
+
 ## Known Limitations
 
 This rule checks callback functions of methods with the given names, *even if* the object which has the method is *not* an array.

diff --git a/lib/rules/array-callback-return.js b/lib/rules/array-callback-return.js
@@ -162,6 +162,10 @@ module.exports = {
                     checkForEach: {
                         type: "boolean",
                         default: false
+                    },
+                    allowVoid: {
+                        type: "boolean",
+                        default: false
                     }
                 },
                 additionalProperties: false
@@ -178,7 +182,7 @@ module.exports = {
 
     create(context) {
 
-        const options = context.options[0] || { allowImplicit: false, checkForEach: false };
+        const options = context.options[0] || { allowImplicit: false, checkForEach: false, allowVoid: false };
         const sourceCode = context.sourceCode;
 
         let funcInfo = {
@@ -209,6 +213,12 @@ module.exports = {
 
             if (funcInfo.arrayMethodName === "forEach") {
                 if (options.checkForEach && node.type === "ArrowFunctionExpression" && node.expression) {
+                    if (options.allowVoid &&
+                        node.body.type === "UnaryExpression" &&
+                        node.body.operator === "void") {
+                        return;
+                    }
+
                     messageId = "expectedNoReturnValue";
                 }
             } else {
@@ -291,6 +301,12 @@ module.exports = {
 
                     // if checkForEach: true, returning a value at any path inside a forEach is not allowed
                     if (options.checkForEach && node.argument) {
+                        if (options.allowVoid &&
+                            node.argument.type === "UnaryExpression" &&
+                            node.argument.operator === "void") {
+                            return;
+                        }
+
                         messageId = "expectedNoReturnValue";
                     }
                 } else {

diff --git a/tests/lib/rules/array-callback-return.js b/tests/lib/rules/array-callback-return.js
@@ -24,6 +24,8 @@ const checkForEachOptions = [{ checkForEach: true }];
 
 const allowImplicitCheckForEach = [{ allowImplicit: true, checkForEach: true }];
 
+const checkForEachAllowVoid = [{ checkForEach: true, allowVoid: true }];
+
 ruleTester.run("array-callback-return", rule, {
     valid: [
 
@@ -114,6 +116,13 @@ ruleTester.run("array-callback-return", rule, {
         { code: "foo.every(function() { try { bar(); } finally { return 1; } })", options: checkForEachOptions },
         { code: "foo.every(function() { return; })", options: allowImplicitCheckForEach },
 
+        // options: { checkForEach: true, allowVoid: true }
+        { code: "foo.forEach((x) => void x)", options: checkForEachAllowVoid, parserOptions: { ecmaVersion: 6 } },
+        { code: "foo.forEach((x) => void bar(x))", options: checkForEachAllowVoid, parserOptions: { ecmaVersion: 6 } },
+        { code: "foo.forEach(function (x) { return void bar(x); })", options: checkForEachAllowVoid, parserOptions: { ecmaVersion: 6 } },
+        { code: "foo.forEach((x) => { return void bar(x); })", options: checkForEachAllowVoid, parserOptions: { ecmaVersion: 6 } },
+        { code: "foo.forEach((x) => { if (a === b) { return void a; } bar(x) })", options: checkForEachAllowVoid, parserOptions: { ecmaVersion: 6 } },
+
         "Arrow.from(x, function() {})",
         "foo.abc(function() {})",
         "every(function() {})",
@@ -217,6 +226,18 @@ ruleTester.run("array-callback-return", rule, {
         { code: "foo.filter(function foo() {})", options: checkForEachOptions, errors: [{ messageId: "expectedInside", data: { name: "function 'foo'", arrayMethodName: "Array.prototype.filter" } }] },
         { code: "foo.filter(function foo() { return; })", options: checkForEachOptions, errors: [{ messageId: "expectedReturnValue", data: { name: "function 'foo'", arrayMethodName: "Array.prototype.filter" } }] },
         { code: "foo.every(cb || function() {})", options: checkForEachOptions, errors: ["Array.prototype.every() expects a return value from function."] },
+        { code: "foo.forEach((x) => void x)", options: checkForEachOptions, parserOptions: { ecmaVersion: 6 }, errors: [{ messageId: "expectedNoReturnValue" }] },
+        { code: "foo.forEach((x) => void bar(x))", options: checkForEachOptions, parserOptions: { ecmaVersion: 6 }, errors: [{ messageId: "expectedNoReturnValue" }] },
+        { code: "foo.forEach((x) => { return void bar(x); })", options: checkForEachOptions, parserOptions: { ecmaVersion: 6 }, errors: [{ messageId: "expectedNoReturnValue" }] },
+        { code: "foo.forEach((x) => { if (a === b) { return void a; } bar(x) })", options: checkForEachOptions, parserOptions: { ecmaVersion: 6 }, errors: [{ messageId: "expectedNoReturnValue" }] },
+
+        // options: { checkForEach: true, allowVoid: true }
+        { code: "foo.forEach((x) => x)", options: checkForEachAllowVoid, parserOptions: { ecmaVersion: 6 }, errors: [{ messageId: "expectedNoReturnValue" }] },
+        { code: "foo.forEach((x) => !x)", options: checkForEachAllowVoid, parserOptions: { ecmaVersion: 6 }, errors: [{ messageId: "expectedNoReturnValue" }] },
+        { code: "foo.forEach((x) => { return x; })", options: checkForEachAllowVoid, parserOptions: { ecmaVersion: 6 }, errors: [{ messageId: "expectedNoReturnValue" }] },
+        { code: "foo.forEach((x) => { return !x; })", options: checkForEachAllowVoid, parserOptions: { ecmaVersion: 6 }, errors: [{ messageId: "expectedNoReturnValue" }] },
+        { code: "foo.forEach((x) => { if (a === b) { return x; } })", options: checkForEachAllowVoid, parserOptions: { ecmaVersion: 6 }, errors: [{ messageId: "expectedNoReturnValue" }] },
+        { code: "foo.forEach((x) => { if (a === b) { return !x } })", options: checkForEachAllowVoid, parserOptions: { ecmaVersion: 6 }, errors: [{ messageId: "expectedNoReturnValue" }] },
 
         // full location tests
         {