useShorthandAssign

Diagnostic Category: lint/style/useShorthandAssign

JavaScript (and super languages)

Since: v1.3.0

Sources:

Same as: operator-assignment

Description

Require assignment operator shorthand where possible.

JavaScript provides shorthand operators combining a variable assignment and simple mathematical operation.

Examples

Invalid

a = a + 1;

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

  ⚠ Assignment (=) can be replaced with operator assignment +=.
  
  > 1 │ a = a + 1;
      │ ^^^^^^^^^
    2 │ 
  
  ℹ Unsafe fix: Use += instead.
  
    1   │ - a·=·a·+·1;
      1 │ + a·+=·1;
    2 2 │

a = a - 1;

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

  ⚠ Assignment (=) can be replaced with operator assignment -=.
  
  > 1 │ a = a - 1;
      │ ^^^^^^^^^
    2 │ 
  
  ℹ Unsafe fix: Use -= instead.
  
    1   │ - a·=·a·-·1;
      1 │ + a·-=·1;
    2 2 │

a = a * 1;

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

  ⚠ Assignment (=) can be replaced with operator assignment *=.
  
  > 1 │ a = a * 1;
      │ ^^^^^^^^^
    2 │ 
  
  ℹ Unsafe fix: Use *= instead.
  
    1   │ - a·=·a·*·1;
      1 │ + a·*=·1;
    2 2 │

Valid

a += 1;

a -= 1;

a *= 1;

How to configure

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