noGlobalAssign (JavaScript)

Language JavaScript (and super languages)

Summary

Rule available since: v1.5.0
Diagnostic Category: lint/suspicious/noGlobalAssign
This rule is recommended, meaning it is enabled by default.
This rule doesn’t have a fix.
The default severity of this rule is error.
Sources:
- Same as no-global-assign
- Same as no-native-reassign

How to configure

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{
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  "linter": {
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    "rules": {
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      "suspicious": {
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        "noGlobalAssign": "error"
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      }
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    }
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  }
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}

Description

Disallow assignments to native objects and read-only global variables.

JavaScript’s environments contain numerous built-in global variables, such as window in browsers and process in Node.js. Assigning values to these global variables can be problematic as it can override essential functionality.

Examples

Invalid

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Object = null;

code-block.js:1:1 lint/suspicious/noGlobalAssign ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━

  ✖ A global variable should not be reassigned.
  
  > 1 │ Object = null;
      │ ^^^^^^
    2 │ 
  
  ℹ Assigning to a global variable can override essential functionality.
  
  ℹ Remove the assignment, or declare a local variable with a different name and assign to that instead.

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window = {};

code-block.js:1:1 lint/suspicious/noGlobalAssign ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━

  ✖ A global variable should not be reassigned.
  
  > 1 │ window = {};
      │ ^^^^^^
    2 │ 
  
  ℹ Assigning to a global variable can override essential functionality.
  
  ℹ Remove the assignment, or declare a local variable with a different name and assign to that instead.

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undefined = true;

code-block.js:1:1 lint/suspicious/noGlobalAssign ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━

  ✖ A global variable should not be reassigned.
  
  > 1 │ undefined = true;
      │ ^^^^^^^^^
    2 │ 
  
  ℹ Assigning to a global variable can override essential functionality.
  
  ℹ Remove the assignment, or declare a local variable with a different name and assign to that instead.

Valid

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a = 0;

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let window;
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window = {};