improve 'no-identical-functions': add option for min function size (#325)

* Add min lines configuration for no-identical-functions rule

* Improve options schema

* Bring back classic options schema

Co-authored-by: raspopov.iv <[email protected]>

Author: vilchik-elena

docs/rules/no-identical-functions.md

@@ -27,12 +27,19 @@ function calculateCode() {
   doOtherThing();
   return code;
 }
-  
+
 function getName() {
   return calculateCode();
 }
 ```
 
-## Exceptions
+## Configuration
+
+This rule has a numeric option (defaulted to 3) to specify the minimum number of lines to trigger an issue. Lines between curly braces are taken into consideration.
 
-Functions with fewer than 3 lines are ignored.
+```json
+{
+  "no-identical-functions": "error",
+  "no-identical-functions": ["error", 5]
+}
+```

src/rules/no-identical-functions.ts

@@ -24,6 +24,8 @@ import { areEquivalent } from '../utils/equivalence';
 import { getMainFunctionTokenLocation, report, issueLocation } from '../utils/locations';
 import docsUrl from '../utils/docs-url';
 
+const DEFAULT_MIN_LINES = 3;
+
 type FunctionNode =
   | TSESTree.FunctionDeclaration
   | TSESTree.FunctionExpression
@@ -32,7 +34,9 @@ type FunctionNode =
 const message =
   'Update this function so that its implementation is not identical to the one on line {{line}}.';
 
-const rule: TSESLint.RuleModule<string, string[]> = {
+type Options = (number | 'sonar-runtime')[];
+
+const rule: TSESLint.RuleModule<string, Options> = {
   meta: {
     messages: {
       identicalFunctions: message,
@@ -45,13 +49,16 @@ const rule: TSESLint.RuleModule<string, string[]> = {
       url: docsUrl(__filename),
     },
     schema: [
+      { type: 'integer', minimum: 3 },
       {
         enum: ['sonar-runtime'],
       },
     ],
   },
-  create(context: TSESLint.RuleContext<string, string[]>) {
+  create(context) {
     const functions: Array<{ function: FunctionNode; parent: TSESTree.Node | undefined }> = [];
+    const minLines: number =
+      typeof context.options[0] === 'number' ? context.options[0] : DEFAULT_MIN_LINES;
 
     return {
       FunctionDeclaration(node: TSESTree.Node) {
@@ -136,7 +143,7 @@ const rule: TSESLint.RuleModule<string, string[]> = {
         const firstLine = tokens[0].loc.start.line;
         const lastLine = tokens[tokens.length - 1].loc.end.line;
 
-        return lastLine - firstLine > 1;
+        return lastLine - firstLine + 1 >= minLines;
       }
 
       return false;

tests/rules/no-identical-functions.test.ts

@@ -70,6 +70,23 @@ ruleTester.run('no-identical-functions', rule, {
       )
       `,
     },
+    {
+      code: `
+      const x = {
+        foo() {
+          console.log("Hello");
+          console.log("World");
+          return 42;
+        },
+
+        bar() {
+          console.log("Hello");
+          console.log("World");
+          return 42;
+        },
+      };`,
+      options: [4],
+    },
   ],
   invalid: [
     {
@@ -300,7 +317,7 @@ ruleTester.run('no-identical-functions', rule, {
           return 42;
         },
       };`,
-      options: ['sonar-runtime'],
+      options: [3, 'sonar-runtime'],
       errors: [
         encodedMessage(3, 10, [
           { line: 3, column: 8, endLine: 3, endColumn: 11, message: 'Original implementation' },
@@ -314,17 +331,19 @@ ruleTester.run('no-identical-functions', rule, {
         //     ^^^^>
         return [
           1,
+          2,
         ];
       }
       function bar1() {
     //         ^^^^
         return [
           1,
+          2,
         ];
       }`,
-      options: ['sonar-runtime'],
+      options: [4, 'sonar-runtime'],
       errors: [
-        encodedMessage(2, 8, [
+        encodedMessage(2, 9, [
           { line: 2, column: 15, endLine: 2, endColumn: 19, message: 'Original implementation' },
         ]),
       ],