enforce for jsx option

ihordiachenko · May 9, 2021 · 7f1f0a7 · 7f1f0a7
1 parent aa9f674
commit 7f1f0a7
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Showing 3 changed files with 56 additions and 9 deletions.
diff --git a/README.md b/README.md
@@ -71,6 +71,7 @@ This rule, in its default state, does not require any arguments. If you would li
 - `allowShortCircuit` set to `true` will allow you to use short circuit evaluations in your expressions (Default: `false`).
 - `allowTernary` set to `true` will enable you to use ternary operators in your expressions similarly to short circuit evaluations (Default: `false`).
 - `allowTaggedTemplates` set to `true` will enable you to use tagged template literals in your expressions (Default: `false`).
+- `enforceForJSX` set to `true` will flag unused JSX element expressions (Default: `false`).
 
 These options allow unused expressions only if all of the code paths either directly change the state (for example, assignment statement) or could have side effects (for example, function call).
 

diff --git a/lib/rules/no-unused-expressions.js b/lib/rules/no-unused-expressions.js
@@ -48,6 +48,10 @@ module.exports = {
                     },
                     allowTaggedTemplates: {
                         type: "boolean"
+                    },
+                    enforceForJSX: {
+                        type: "boolean",
+                        default: false
                     }
                 },
                 additionalProperties: false
@@ -62,8 +66,8 @@ module.exports = {
         var config = context.options[0] || {},
             allowShortCircuit = config.allowShortCircuit || false,
             allowTernary = config.allowTernary || false,
-            allowTaggedTemplates = config.allowTaggedTemplates || false;
-
+            allowTaggedTemplates = config.allowTaggedTemplates || false,
+            enforceForJSX = config.enforceForJSX || false;
 
         /**
          * @param {ASTNode} node - any node
@@ -135,6 +139,12 @@ module.exports = {
             FunctionExpression: alwaysTrue,
             Identifier: alwaysTrue,
             Literal: alwaysTrue,
+            JSXElement() {
+                return enforceForJSX;
+            },
+            JSXFragment() {
+                return enforceForJSX;
+            },
             LogicalExpression(node) {
                 if (allowShortCircuit) {
                     return Checker.isDisallowed(node.right);

diff --git a/tests/lib/rules/no-unused-expressions.js b/tests/lib/rules/no-unused-expressions.js
@@ -83,6 +83,29 @@ ruleTester.run("no-unused-expressions", rule, {
             code: "obj?.foo(\"bar\")",
             parserOptions: { ecmaVersion: 11 }
         },
+        // JSX
+        {
+            code: "<div />",
+            parserOptions: { ecmaFeatures: { jsx: true } }
+        },
+        {
+            code: "<></>",
+            parserOptions: { ecmaFeatures: { jsx: true } }
+        },
+        {
+            code: "var partial = <div />",
+            parserOptions: { ecmaFeatures: { jsx: true } }
+        },
+        {
+            code: "var partial = <div />",
+            options: [{ enforceForJSX: true }],
+            parserOptions: { ecmaFeatures: { jsx: true } }
+        },
+        {
+            code: "var partial = <></>",
+            options: [{ enforceForJSX: true }],
+            parserOptions: { ecmaFeatures: { jsx: true } }
+        },
 
         // Chai statements
         "expect(foo).to.be.true;",
@@ -98,11 +121,11 @@ ruleTester.run("no-unused-expressions", rule, {
         { code: "{0}", errors: [{ message: "Expected an assignment or function call and instead saw an expression.", type: "ExpressionStatement"}]},
         { code: "[]", errors: [{ message: "Expected an assignment or function call and instead saw an expression.", type: "ExpressionStatement"}]},
         { code: "a && b();", errors: [{ message: "Expected an assignment or function call and instead saw an expression.", type: "ExpressionStatement"}]},
-        { code: "a() || false", errors: [{ message: "Expected an assignment or function call and instead saw an expression.", type: "ExpressionStatement" }]},
-        { code: "a || (b = c)", errors: [{ message: "Expected an assignment or function call and instead saw an expression.", type: "ExpressionStatement" }]},
-        { code: "a ? b() || (c = d) : e", errors: [{ message: "Expected an assignment or function call and instead saw an expression.", type: "ExpressionStatement" }]},
-        { code: "a && b()", options: [{ allowTernary: true }], errors: [{ message: "Expected an assignment or function call and instead saw an expression.", type: "ExpressionStatement" }]},
-        { code: "a ? b() : c()", options: [{ allowShortCircuit: true }], errors: [{ message: "Expected an assignment or function call and instead saw an expression.", type: "ExpressionStatement" }]},
+        { code: "a() || false", errors: [{ messageId: "unusedExpression", type: "ExpressionStatement" }]},
+        { code: "a || (b = c)", errors: [{ messageId: "unusedExpression", type: "ExpressionStatement" }]},
+        { code: "a ? b() || (c = d) : e", errors: [{ messageId: "unusedExpression", type: "ExpressionStatement" }]},
+        { code: "a && b()", options: [{ allowTernary: true }], errors: [{ messageId: "unusedExpression", type: "ExpressionStatement" }]},
+        { code: "a ? b() : c()", options: [{ allowShortCircuit: true }], errors: [{ messageId: "unusedExpression", type: "ExpressionStatement" }]},
         { code: "a || b", options: [{ allowShortCircuit: true }], errors: [{ message: "Expected an assignment or function call and instead saw an expression.", type: "ExpressionStatement"}]},
         { code: "a() && b", options: [{ allowShortCircuit: true }], errors: [{ message: "Expected an assignment or function call and instead saw an expression.", type: "ExpressionStatement"}]},
         { code: "a ? b : 0", options: [{ allowTernary: true }], errors: [{ message: "Expected an assignment or function call and instead saw an expression.", type: "ExpressionStatement"}]},
@@ -160,9 +183,22 @@ ruleTester.run("no-unused-expressions", rule, {
             parserOptions: { ecmaVersion: 2020 },
             errors: [{ messageId: "unusedExpression", type: "ExpressionStatement" }]
         },
+        // JSX
+        {
+            code: "<div />",
+            options: [{ enforceForJSX: true }],
+            parserOptions: { ecmaFeatures: { jsx: true } },
+            errors: [{ messageId: "unusedExpression", type: "ExpressionStatement" }]
+        },
+        {
+            code: "<></>",
+            options: [{ enforceForJSX: true }],
+            parserOptions: { ecmaFeatures: { jsx: true } },
+            errors: [{ messageId: "unusedExpression", type: "ExpressionStatement" }]
+        },
 
         // Chai statements
-        { code: "foo.expect('bar').not.to.pass;", errors: [{ message: "Expected an assignment or function call and instead saw an expression.", type: "ExpressionStatement" }]},
-        { code: "should.not.pass;", errors: [{ message: "Expected an assignment or function call and instead saw an expression.", type: "ExpressionStatement" }] },
+        { code: "foo.expect('bar').not.to.pass;", errors: [{ messageId: "unusedExpression", type: "ExpressionStatement" }]},
+        { code: "should.not.pass;", errors: [{ messageId: "unusedExpression", type: "ExpressionStatement" }] },
     ]
 });