noMultiAssign

JavaScript (and super languages)

Note

This rule has been implemented but not released yet. It will be available in the next release.

Caution

This rule is part of the nursery group. This means that it is experimental and the behavior can change at any time.

Summary

• Diagnostic Category: lint/nursery/noMultiAssign
• This rule doesn’t have a fix.
• The default severity of this rule is information.
• Sources:
  • Inspired from no-multi-assign

How to configure

biome.json

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

Description

Disallow use of chained assignment expressions

Chaining the assignment of variables can lead to unexpected results and be difficult to read.

Examples

Invalid

const foo = bar = "baz";

code-block.js:1:7 lint/nursery/noMultiAssign ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━

  ℹ Unexpected chained assignment.
  
  > 1 │ const foo = bar = “baz”;
      │       ^^^^^^^^^^^^^^^^^
    2 │ 
  
  ℹ Variables with chained assignments in declarations may cause unintended implicit globals or unexpected scoping.
  
  ℹ Split into separate assignments.
  

Valid

const foo = "baz";
const bar = "baz";

Related links

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