noUselessThisAlias (JavaScript)

Language JavaScript (and super languages)

Summary

Rule available since: v1.0.0
Diagnostic Category: lint/complexity/noUselessThisAlias
This rule is recommended, meaning it is enabled by default.
This rule has a safe fix.
The default severity of this rule is information.
Sources:
- Inspired from @typescript-eslint/no-this-alias

How to configure

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{
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  "linter": {
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    "rules": {
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      "complexity": {
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        "noUselessThisAlias": "error"
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      }
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    }
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  }
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}

Description

Disallow aliases for this when this can be used directly.

Arrow functions use this from their surrounding scope. In that situation, assigning this to another variable adds an unnecessary name without changing which value is used.

Examples

Invalid

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class A {
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    method() {
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        const self = this;
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        return () => {
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            return self;
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        }
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    }
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}

code-block.js:3:15 lint/complexity/noUselessThisAlias  FIXABLE  ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━

  ℹ This aliasing of this is unnecessary.
  
    1 │ class A {
    2 │     method() {
  > 3 │         const self = this;
      │               ^^^^^^^^^^^
    4 │         return () => {
    5 │             return self;
  
  ℹ Arrow functions inherits `this` from their enclosing scope.
  
  ℹ Safe fix: Use this instead of an alias.
  
    1 1 │   class A {
    2 2 │       method() {
    3   │ - ········const·self·=·this;
    4 3 │           return () => {
    5   │ - ············return·self;
      4 │ + ············return·this;
    6 5 │           }
    7 6 │       }

Valid

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class A {
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    method() {
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        const self = this;
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        return function() {
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            this.g();
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            return self;
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        }
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    }
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}