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Severity: warning
Category: lint
Stage: Stage 3

Description

An anonymous function expression passed directly as a call argument is flagged in favour of an arrow function. Arrows are shorter, preserve lexical this, and match idiomatic modern JS.

Named function expressions (for recursion or stack traces) are not flagged.

Example

// ✗ lint warning
xs.map(function (x) { return x + 1 })   // SJS-L008

Fix

Use an arrow function:

// ✓ correct
xs.map((x) => x + 1)

// ✓ correct — named function is allowed
xs.map(function keep(x) { return x })

Configuration

{
  "lint": {
    "L008": "error" | "warn" | "off"
  }
}

Default: "warn" in standard mode, "error" in --strict mode.

Related codes

  • SJS-L001 — prefer const over let
Documentation