invalid array length JavaScript Origin: On your device Last updated 13 Oct 2026

RangeError: Invalid array length

An array was created or resized with a negative, fractional or enormous length.

Exact message you may see Invalid array length
Seen on: JavaScript

Meaning

new Array(n) with n negative/NaN, or array.length set to an invalid value. Often n comes from a failed calculation.

Common causes

  • new Array(-1) or new Array(NaN)
  • Length from a bad calculation or input
  • Infinite loop pushing until memory limits

⚡ Quick fix

  1. Validate n is a non-negative integer
  2. Use Array.from({ length: n })

Detailed fix by platform

JavaScript

  1. `const n = Math.max(0, Math.floor(count)
  2. 0); const rows = Array.from({ length: n }, () => []);`

How to diagnose

  1. Value — What length was requested?
  2. Recent change — Did it start after a deploy, upgrade, or configuration change? Compare with the last working version.

🔧 Still not fixed?

Many errors look alike. If the steps above didn’t solve it, one of these is probably what you’re facing:

Where this error sits

Origin: On your device. Errors that are often confused with or caused by this one (click to open):

AbortError — AbortError: The user aborted a request. / signal is aborted without reason (JavaScript)AbortErrorArray offset on null — Warning: Trying to access array offset on value of type null (PHP)Array offset on nullArrayIndexOutOfBoundsException — java.lang.ArrayIndexOutOfBoundsException: Index 5 out of bounds for length 5 (Java)ArrayIndexOutOfBounds…Aw, Snap! — Chrome: Aw, Snap! Something went wrong while displaying this webpage. Error code: STATUS_ACCESS_VIOLATION / SIGILL / Out of Memory (Browser)Aw, Snap!body already used — TypeError: Failed to execute 'json' on 'Response': body stream already read (JavaScript)body already usedreading length — TypeError: Cannot read properties of undefined (reading 'length') (JavaScript)reading lengthreduce empty — TypeError: Reduce of empty array with no initial value (JavaScript)reduce emptyUndefined array key — Warning: Undefined array key / Undefined index (PHP)Undefined array keyinvalid a…

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