noErasingOperation (JavaScript)

Language JavaScript (and super languages)

Summary

Rule available since: v2.6.6
Diagnostic Category: lint/nursery/noErasingOperation
This rule doesn’t have a fix.
The default severity of this rule is error.
Sources:
- Same as oxc/erasing-op
- Same as erasing_op

How to configure

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

Description

Disallow operations with zero that always result in zero.

Multiplying a number by 0, combining it with 0 using the bitwise AND operator (&), or dividing 0 by a number gives 0 no matter what the other number is. The other number has no effect on the result, so code like x * 0 is most likely a mistake, such as a leftover from debugging or a typo. If the result should be zero, write 0 directly.

A few special values produce a different result. For example, NaN * 0 and Infinity * 0 are both NaN, and -5 * 0 is -0.

The rule only reports a 0 that is written as a number, such as 0 or 0.0. It doesn’t report variables that contain zero, 0n (a BigInt zero), or 0 / 0, which results in NaN instead of zero.

Examples

Invalid

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const total = price * 0;

code-block.js:1:15 lint/nursery/noErasingOperation ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━

  ✖ This operation always results in zero.
  
  > 1 │ const total = price * 0;
      │               ^^^^^^^^^
    2 │ 
  
  ℹ Multiplying by zero gives zero, so the other value has no effect on the result.
  
  ℹ This is likely a mistake. If the result should be zero, replace the operation with 0.
  
  ℹ This rule belongs to the nursery group, which means it is not yet stable and may change in the future. Visit https://biomejs.dev/linter/#nursery for more information.

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const flags = options & 0;

code-block.js:1:15 lint/nursery/noErasingOperation ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━

  ✖ This operation always results in zero.
  
  > 1 │ const flags = options & 0;
      │               ^^^^^^^^^^^
    2 │ 
  
  ℹ A bitwise AND with zero gives zero, so the other value has no effect on the result.
  
  ℹ This is likely a mistake. If the result should be zero, replace the operation with 0.
  
  ℹ This rule belongs to the nursery group, which means it is not yet stable and may change in the future. Visit https://biomejs.dev/linter/#nursery for more information.

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const ratio = 0 / count;

code-block.js:1:15 lint/nursery/noErasingOperation ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━

  ✖ This operation always results in zero.
  
  > 1 │ const ratio = 0 / count;
      │               ^^^^^^^^^
    2 │ 
  
  ℹ Dividing zero by a number gives zero, so the other value has no effect on the result.
  
  ℹ This is likely a mistake. If the result should be zero, replace the operation with 0.
  
  ℹ This rule belongs to the nursery group, which means it is not yet stable and may change in the future. Visit https://biomejs.dev/linter/#nursery for more information.

Valid

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const total = price * quantity;
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const flags = options | 0;
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const ratio = count / 0;
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const zero = 0;