no-this-alias
Disallow aliasing
this
.
Extending "plugin:@typescript-eslint/recommended"
in an ESLint configuration enables this rule.
Assigning a variable to this
instead of properly using arrow lambdas may be a symptom of pre-ES6 practices
or not managing scope well.
module.exports = {
"rules": {
"@typescript-eslint/no-this-alias": "error"
}
};
Try this rule in the playground ↗
Examples
- ❌ Incorrect
- ✅ Correct
const self = this;
setTimeout(function () {
self.doWork();
});
Open in PlaygroundsetTimeout(() => {
this.doWork();
});
Open in PlaygroundOptions
This rule accepts the following options:
type Options = [
{
/** Whether to ignore destructurings, such as `const { props, state } = this`. */
allowDestructuring?: boolean;
/** Names to ignore, such as ["self"] for `const self = this;`. */
allowedNames?: string[];
},
];
const defaultOptions: Options = [
{ allowDestructuring: true, allowedNames: [] },
];
allowDestructuring
It can sometimes be useful to destructure properties from a class instance, such as retrieving multiple properties from the instance in one of its methods.
allowDestructuring
allows those destructures and is true
by default.
You can explicitly disallow them by setting allowDestructuring
to false
.
Examples of code for the { "allowDestructuring": false }
option:
- ❌ Incorrect
- ✅ Correct
class ComponentLike {
props: unknown;
state: unknown;
render() {
const { props, state } = this;
console.log(props);
console.log(state);
}
}
Open in Playgroundclass ComponentLike {
props: unknown;
state: unknown;
render() {
console.log(this.props);
console.log(this.state);
}
}
Open in PlaygroundallowedNames
no-this-alias
can alternately be used to allow only a specific list of names as this
aliases.
We recommend against this except as a transitory step towards fixing all rule violations.
Examples of code for the { "allowedNames": ["self"] }
option:
- ❌ Incorrect
- ✅ Correct
class Example {
method() {
const that = this;
}
}
Open in Playgroundclass Example {
method() {
const self = this;
}
}
Open in PlaygroundWhen Not To Use It
If your project is structured in a way that it needs to assign this
to variables, this rule is likely not for you.
If only a subset of your project assigns this
to variables then you might consider using ESLint disable comments for those specific situations instead of completely disabling this rule.