Update no-duplicate-string: Add ignoreStrings option (#405)

Author: yassin-kammoun-sonarsource

docs/rules/no-duplicate-string.md

@@ -7,11 +7,19 @@ To prevent generating some false-positives, literals having less than 10 charact
 
 ## Configuration
 
-Number of times a literal must be duplicated to trigger an issue. Default is 3.
+Number of times a literal must be duplicated to trigger an issue. Default is `3`.
 
 ```json
 {
   "no-duplicate-string": "error",
-  "no-duplicate-string": ["error", 5]
+  "no-duplicate-string": ["error", { "threshold": 5 }]
 }
 ```
+
+Comma-separated list of strings that must be ignored. Default is `"application/json"`.
+
+```json
+{
+  "no-duplicate-string": "error",
+  "no-duplicate-string": ["error", { "ignoreStrings": "foo,bar,baz" }]
+}

ruling/snapshots/no-duplicate-string

@@ -142,7 +142,6 @@ src/express/lib/response.js: 132,194
 src/freeCodeCamp/common/app/redux/utils.test.js: 54
 src/freeCodeCamp/common/app/routes/Challenges/utils/index.test.js: 24,25,28,90,112,164,274,321,322,350,405,477,597,811
 src/freeCodeCamp/common/app/routes/Challenges/views/step/redux/step-challenge-epic.test.js: 48,62,69
-src/freeCodeCamp/common/utils/ajax-stream.js: 283
 src/freeCodeCamp/public/js/calculator.js: 9,16,149
 src/freeCodeCamp/public/js/lib/loop-protect/loop-protect.js: 283
 src/freeCodeCamp/seed/unpackedChallenge.js: 218,246

src/rules/no-duplicate-string.ts

@@ -25,6 +25,7 @@ import { issueLocation, report } from '../utils/locations';
 
 // Number of times a literal must be duplicated to trigger an issue
 const DEFAULT_THRESHOLD = 3;
+const DEFAULT_IGNORE_STRINGS = 'application/json';
 const MIN_LENGTH = 10;
 const NO_SEPARATOR_REGEXP = /^\w*$/;
 const EXCLUDED_CONTEXTS = [
@@ -36,7 +37,9 @@ const EXCLUDED_CONTEXTS = [
 ];
 const message = 'Define a constant instead of duplicating this literal {{times}} times.';
 
-type Options = (number | 'sonar-runtime')[];
+type Options =
+  | [{ threshold?: number; ignoreStrings?: string } | undefined, 'sonar-runtime']
+  | [{ threshold?: number; ignoreStrings?: string } | undefined];
 type Context = TSESLint.RuleContext<string, Options>;
 
 const rule: TSESLint.RuleModule<string, Options> = {
@@ -52,16 +55,21 @@ const rule: TSESLint.RuleModule<string, Options> = {
       url: docsUrl(__filename),
     },
     schema: [
-      { type: 'integer', minimum: 2 },
+      {
+        type: 'object',
+        properties: {
+          threshold: { type: 'integer', minimum: 2 },
+          ignoreStrings: { type: 'string', default: DEFAULT_IGNORE_STRINGS },
+        },
+      },
       { enum: ['sonar-runtime'] /* internal parameter for rules having secondary locations */ },
     ],
   },
 
   create(context) {
     const literalsByValue: Map<string, TSESTree.Literal[]> = new Map();
-    const threshold: number =
-      typeof context.options[0] === 'number' ? context.options[0] : DEFAULT_THRESHOLD;
-
+    const { threshold, ignoreStrings } = extractOptions(context);
+    const whitelist = ignoreStrings.split(',');
     return {
       Literal: (node: TSESTree.Node) => {
         const literal = node as TSESTree.Literal;
@@ -74,6 +82,7 @@ const rule: TSESLint.RuleModule<string, Options> = {
           const stringContent = literal.value.trim();
 
           if (
+            !whitelist.includes(literal.value) &&
             !isExcludedByUsageContext(context, literal) &&
             stringContent.length >= MIN_LENGTH &&
             !stringContent.match(NO_SEPARATOR_REGEXP)
@@ -130,4 +139,17 @@ function isObjectPropertyKey(parent: TSESTree.Node, literal: TSESTree.Literal) {
   return parent.type === 'Property' && parent.key === literal;
 }
 
+function extractOptions(context: Context) {
+  let threshold: number = DEFAULT_THRESHOLD;
+  let ignoreStrings: string = DEFAULT_IGNORE_STRINGS;
+  const options = context.options[0];
+  if (typeof options?.threshold === 'number') {
+    threshold = options.threshold;
+  }
+  if (typeof options?.ignoreStrings === 'string') {
+    ignoreStrings = options.ignoreStrings;
+  }
+  return { threshold, ignoreStrings };
+}
+
 export = rule;

tests/rules/no-duplicate-string.test.ts

@@ -27,7 +27,13 @@ ruleTester.run('no-duplicate-string', rule, {
     console.log("some message");
     console.log("some message");
     console.log('some message');`,
-      options: [4],
+      options: [{ threshold: 4 }],
+    },
+    {
+      code: ` // too small
+    console.log("a&b");
+    console.log("a&b");
+    console.log("a&b");`,
     },
     {
       code: ` // too small
@@ -151,6 +157,21 @@ ruleTester.run('no-duplicate-string', rule, {
       }
       `,
     },
+    {
+      code: `
+      'application/json';
+      'application/json';
+      'application/json';;
+      `,
+    },
+    {
+      code: `
+      console.log('Hello world!');
+      console.log('Hello world!');
+      console.log('Hello world!');
+      `,
+      options: [{ threshold: 2, ignoreStrings: 'Hello world!' }, 'sonar-runtime'],
+    },
   ],
   invalid: [
     {
@@ -196,7 +217,7 @@ ruleTester.run('no-duplicate-string', rule, {
           endColumn: 31,
         },
       ],
-      options: [2, 'sonar-runtime'],
+      options: [{ threshold: 2 }, 'sonar-runtime'],
     },
     {
       code: `
@@ -228,7 +249,7 @@ ruleTester.run('no-duplicate-string', rule, {
           line: 2,
         },
       ],
-      options: [2],
+      options: [{ threshold: 2 }],
     },
     {
       code: `