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[bug-fix] no-invalid-this / ignore functions w "this" param #3267
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ajafff
suggested changes
Oct 1, 2017
src/rules/noInvalidThisRule.ts
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| @@ -76,6 +78,9 @@ function walk(ctx: Lint.WalkContext<boolean>): void { | |||
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| case ts.SyntaxKind.FunctionDeclaration: | |||
| case ts.SyntaxKind.FunctionExpression: | |||
| if (hasContextualThis(node as ts.FunctionDeclaration)) { | |||
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ts.FunctionLikeDeclaration for correctness
src/rules/noInvalidThisRule.ts
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| @@ -96,3 +101,7 @@ function walk(ctx: Lint.WalkContext<boolean>): void { | |||
| ts.forEachChild(node, cb); | |||
| }); | |||
| } | |||
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| function hasContextualThis(node: ts.FunctionDeclaration): boolean { | |||
| return node.parameters.some((param) => param.name.getText() === "this"); | |||
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return node.parameters.some(isThisParameter);| @@ -1,3 +1,21 @@ | |||
| export function f<T>(this: Observable<T>): Observable<T> { | |||
| const nestedFunction = (this) => { | |||
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arrow functions cannot have a this parameter
We don't need to worry about it, because TypeScript shows an error. But we shouldn't use it in any test
src/rules/noInvalidThisRule.ts
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| @@ -96,3 +101,7 @@ function walk(ctx: Lint.WalkContext<boolean>): void { | |||
| ts.forEachChild(node, cb); | |||
| }); | |||
| } | |||
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| function hasContextualThis(node: ts.FunctionDeclaration): boolean { | |||
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please rename to hasThisParameter (or completely inline it)
This has nothing to do with contextual this. It's about explicitly declared this parameters.
Contextual this looks as follows:
declare function callWithThis(fn: (this: Array<any>) => void): void;
callWithThis(function() {
console.log(this.length); // this is allowed, because `this` is contextually typed to be an array
});To detect that you would need the TypeChecker. I don't think that's worth it, because TypeScript provides the option --noImplicitThis which makes this rule obsolete.
… arrow function w this param from test
ajafff
approved these changes
Oct 2, 2017
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Thanks @aervin |
HyphnKnight
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Apr 9, 2018
amacleay
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Jul 12, 2018
* Keep track of evaluation context: look to the closest parent function and decide if it is allowed to refer to `this` * Fix a false negative in the tests from palantir#3267
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amacleay
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Jul 12, 2018
* Keep track of evaluation context: look to the closest parent function and decide if it is allowed to refer to `this` * Fix a false negative in the tests from palantir#3267
amacleay
added a commit
to amacleay/tslint
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Nov 7, 2018
* Keep track of evaluation context: look to the closest parent function and decide if it is allowed to refer to `this` * Fix a false negative in the tests from palantir#3267
ericanderson
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Dec 12, 2018
* no-invalid-this: false positive for method syntax * Keep track of evaluation context: look to the closest parent function and decide if it is allowed to refer to `this` * Fix a false negative in the tests from #3267 * no-invalid-this: stylistic cleanup
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PR checklist
Overview of change:
Functions with contextual "this" will be ignored.
Is there anything you'd like reviewers to focus on?
Are additional test cases needed?