noSubstr

Diagnostic Category: lint/nursery/noSubstr

JavaScript (and super languages)

Since: v1.8.2

Sources:

Same as: unicorn/prefer-string-slice

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

foo.substr();

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

  ⚠ 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 │

foo.substring();

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

  ⚠ 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

foo.slice(beginIndex, endIndex);

How to configure

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