feat: use-isnan report NaN in indexOf and lastIndexOf with fromIn…

…dex (eslint#18225) * fix: report NaN with fromIndex * revert known limitation title change * add tests with third argument
JoshuaKGoldberg · Mar 23, 2024 · d85c436 · d85c436
1 parent b185eb9
commit d85c436
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diff --git a/docs/src/rules/use-isnan.md b/docs/src/rules/use-isnan.md
@@ -226,6 +226,10 @@ var firstIndex = myArray.indexOf(NaN);
 var lastIndex = myArray.lastIndexOf(NaN);
 
 var indexWithSequenceExpression = myArray.indexOf((doStuff(), NaN));
+
+var firstIndexFromSecondElement = myArray.indexOf(NaN, 1);
+
+var lastIndexFromSecondElement = myArray.lastIndexOf(NaN, 1);
 ```
 
 :::

diff --git a/lib/rules/use-isnan.js b/lib/rules/use-isnan.js
@@ -182,15 +182,15 @@ module.exports = {
 
                 if (
                     (methodName === "indexOf" || methodName === "lastIndexOf") &&
-                    node.arguments.length === 1 &&
+                    node.arguments.length <= 2 &&
                     isNaNIdentifier(node.arguments[0])
                 ) {
 
                     /*
                      * To retain side effects, it's essential to address `NaN` beforehand, which
                      * is not possible with fixes like `arr.findIndex(Number.isNaN)`.
                      */
-                    const isSuggestable = node.arguments[0].type !== "SequenceExpression";
+                    const isSuggestable = node.arguments[0].type !== "SequenceExpression" && !node.arguments[1];
                     const suggestedFixes = [];
 
                     if (isSuggestable) {

diff --git a/tests/lib/rules/use-isnan.js b/tests/lib/rules/use-isnan.js
@@ -263,15 +263,15 @@ ruleTester.run("use-isnan", rule, {
             options: [{ enforceForIndexOf: true }]
         },
         {
-            code: "foo.lastIndexOf(NaN, b)",
+            code: "foo.lastIndexOf(NaN, b, c)",
             options: [{ enforceForIndexOf: true }]
         },
         {
             code: "foo.indexOf(a, b)",
             options: [{ enforceForIndexOf: true }]
         },
         {
-            code: "foo.lastIndexOf(NaN, NaN)",
+            code: "foo.lastIndexOf(NaN, NaN, b)",
             options: [{ enforceForIndexOf: true }]
         },
         {
@@ -340,11 +340,11 @@ ruleTester.run("use-isnan", rule, {
             options: [{ enforceForIndexOf: true }]
         },
         {
-            code: "foo.lastIndexOf(Number.NaN, b)",
+            code: "foo.lastIndexOf(Number.NaN, b, c)",
             options: [{ enforceForIndexOf: true }]
         },
         {
-            code: "foo.lastIndexOf(Number.NaN, NaN)",
+            code: "foo.lastIndexOf(Number.NaN, NaN, b)",
             options: [{ enforceForIndexOf: true }]
         },
         {
@@ -1289,6 +1289,86 @@ ruleTester.run("use-isnan", rule, {
                 data: { methodName: "lastIndexOf" },
                 suggestions: []
             }]
+        },
+        {
+            code: "foo.indexOf(NaN, 1)",
+            options: [{ enforceForIndexOf: true }],
+            languageOptions: { ecmaVersion: 2020 },
+            errors: [{
+                messageId: "indexOfNaN",
+                data: { methodName: "indexOf" },
+                suggestions: []
+            }]
+        },
+        {
+            code: "foo.lastIndexOf(NaN, 1)",
+            options: [{ enforceForIndexOf: true }],
+            languageOptions: { ecmaVersion: 2020 },
+            errors: [{
+                messageId: "indexOfNaN",
+                data: { methodName: "lastIndexOf" },
+                suggestions: []
+            }]
+        },
+        {
+            code: "foo.indexOf(NaN, b)",
+            options: [{ enforceForIndexOf: true }],
+            languageOptions: { ecmaVersion: 2020 },
+            errors: [{
+                messageId: "indexOfNaN",
+                data: { methodName: "indexOf" },
+                suggestions: []
+            }]
+        },
+        {
+            code: "foo.lastIndexOf(NaN, b)",
+            options: [{ enforceForIndexOf: true }],
+            languageOptions: { ecmaVersion: 2020 },
+            errors: [{
+                messageId: "indexOfNaN",
+                data: { methodName: "lastIndexOf" },
+                suggestions: []
+            }]
+        },
+        {
+            code: "foo.indexOf(Number.NaN, b)",
+            options: [{ enforceForIndexOf: true }],
+            languageOptions: { ecmaVersion: 2020 },
+            errors: [{
+                messageId: "indexOfNaN",
+                data: { methodName: "indexOf" },
+                suggestions: []
+            }]
+        },
+        {
+            code: "foo.lastIndexOf(Number.NaN, b)",
+            options: [{ enforceForIndexOf: true }],
+            languageOptions: { ecmaVersion: 2020 },
+            errors: [{
+                messageId: "indexOfNaN",
+                data: { methodName: "lastIndexOf" },
+                suggestions: []
+            }]
+        },
+        {
+            code: "foo.lastIndexOf(NaN, NaN)",
+            options: [{ enforceForIndexOf: true }],
+            languageOptions: { ecmaVersion: 2020 },
+            errors: [{
+                messageId: "indexOfNaN",
+                data: { methodName: "lastIndexOf" },
+                suggestions: []
+            }]
+        },
+        {
+            code: "foo.indexOf((1, NaN), 1)",
+            options: [{ enforceForIndexOf: true }],
+            languageOptions: { ecmaVersion: 2020 },
+            errors: [{
+                messageId: "indexOfNaN",
+                data: { methodName: "indexOf" },
+                suggestions: []
+            }]
         }
     ]
 });