noSubstr

JavaScript (and super languages)

Summary

Rule available since: v1.8.2
Diagnostic Category: lint/style/noSubstr
This rule has an unsafe fix.
The default severity of this rule is information.
Sources:
- Same as unicorn/prefer-string-slice

How to configure

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{
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  "linter": {
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    "rules": {
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      "style": {
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        "noSubstr": "error"
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      }
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    }
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  }
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}

Description

Enforce the use of String.slice() over String.substr() and String.substring().

String.slice() is preferred over String.substr() and String.substring() because it is a more popular option with clearer behavior, and it has a consistent counterpart in arrays.

Note that String.substr, String.substring and String.slice are not identical when arguments are passed. For detailed differences, refer to the MDN documentation:

Examples

Invalid

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foo.substr();

code-block.js:1:5 lint/style/noSubstr  FIXABLE  ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━

  ℹ Avoid using substr and consider using slice instead.
  
  > 1 │ foo.substr();
      │     ^^^^^^
    2 │ 
  
  ℹ slice is more commonly used and has a less surprising behavior.
  
  ℹ See MDN web docs for more details.
  
  ℹ Unsafe fix: Use .slice() instead.
  
    1   │ - foo.substr();
      1 │ + foo.slice();
    2 2 │

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foo.substring();

code-block.js:1:5 lint/style/noSubstr  FIXABLE  ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━

  ℹ Avoid using substring and consider using slice instead.
  
  > 1 │ foo.substring();
      │     ^^^^^^^^^
    2 │ 
  
  ℹ slice is more commonly used and has a less surprising behavior.
  
  ℹ See MDN web docs for more details.
  
  ℹ Unsafe fix: Use .slice() instead.
  
    1   │ - foo.substring();
      1 │ + foo.slice();
    2 2 │

Valid

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foo.slice(beginIndex, endIndex);