tools: add fixer for no-let-in-for-declaration

PR-URL: #16642 Refs: #16636 Reviewed-By: Anatoli Papirovski <[email protected]> Reviewed-By: Gireesh Punathil <[email protected]> Reviewed-By: Tobias Nießen <[email protected]>

Author: starkwang

test/parallel/test-eslint-no-let-in-for-declaration.js

@@ -24,14 +24,17 @@ ruleTester.run('no-let-in-for-declaration', rule,{
 invalid: [
 {
 code: 'for (let foo = 1;);',
+output: 'for (var foo = 1;);',
 errors: [{ message }]
 },
 {
 code: 'for (let foo in bar);',
+output: 'for (var foo in bar);',
 errors: [{ message }]
 },
 {
 code: 'for (let foo of bar);',
+output: 'for (var foo of bar);',
 errors: [{ message }]
 }
 ]

tools/eslint-rules/no-let-in-for-declaration.js

@@ -14,7 +14,7 @@
 
 module.exports={
 create(context){
-
+constsourceCode=context.getSourceCode();
 constmsg='Use of `let` as the loop variable in a for-loop is '+
 'not recommended. Please use `var` instead.';
 
@@ -23,7 +23,12 @@ module.exports ={
  */
 functiontestForLoop(node){
 if(node.init&&node.init.kind==='let'){
-context.report(node.init,msg);
+context.report({
+node: node.init,
+message: msg,
+fix: (fixer)=>
+fixer.replaceText(sourceCode.getFirstToken(node.init),'var')
+});
 }
 }
 
@@ -33,7 +38,12 @@ module.exports ={
  */
 functiontestForInOfLoop(node){
 if(node.left&&node.left.kind==='let'){
-context.report(node.left,msg);
+context.report({
+node: node.left,
+message: msg,
+fix: (fixer)=>
+fixer.replaceText(sourceCode.getFirstToken(node.left),'var')
+});
 }
 }