1 KB JS sample file

A JS file of exactly 1,024 bytes. It is a valid JavaScript source file file, generated for this site and checked with an independent parser.

sample-js-1kb.js

1 KB1,024 bytes

Download 1 KB JS

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Type: text/javascript
SHA-256: a38f60e8a19b500b47463c4f21707d36ad7f62106284289cbebd64167a353598
Direct URL: https://sampletestfiles.com/downloads/js/sample-js-1kb.js

What is in this file

A "records" array of 4 object literals and two small helper functions. Line comments at the end bring the script to the exact size.

Array entries	4
Syntax	ECMAScript 2015+, strict mode
Side effects on load	None
Encoding	UTF-8 (ASCII characters only)

How the file begins

The opening lines of sample-js-1kb.js, exactly as they appear in the file.

// SampleTestFiles sample JavaScript file (1 KB)
// Plain ECMAScript with no dependencies. It defines data and two helper functions and runs nothing on load.
'use strict';

const records = [
  { id: 1, name: 'Ethan Zeller', email: 'ethan.zeller1@example.com', plan: 'team', balance: 2769.84, active: true },
  { id: 2, name: 'Elena Underhill', email: 'elena.underhill2@example.net', plan: 'free', balance: 4647.61, active: true },
  { id: 3, name: 'Ethan Farrow', email: 'ethan.farrow3@example.org', plan: 'business', balance: 536.73, active: false },
  { id: 4, name: 'Victor Brennan', email: 'victor.brennan4@example.com', plan: 'business', balance: 2410.43, active: true },
];

function totalBalance(list) {
  return list.reduce((sum, item) => sum + item.balance, 0);
}

Preview

Shows the file contents.

Where 1 KB matters

The smallest practical test file: 1,024 bytes, small enough to travel in a single network packet. These are the default limits a file of this size is useful for testing:

System	Limit	Note
Ethernet	1,500 bytes (typical MTU)	A 1 KB payload fits in one packet with its headers.
Browser cookies	4,096 bytes per cookie	1 KB is well inside the limit; the 5 KB sample is over it.

All 1 KB sample files

Use this file for

Smoke tests in CI that must run in milliseconds
Testing bundlers and minifiers with large inputs
Checking syntax highlighters and editors

Testing notes for JS

The old types application/javascript and application/x-javascript are obsolete; text/javascript is the registered type.
Never execute an uploaded script. Treat .js uploads as text to be stored or analysed.

JS format reference

Technical details

File name	sample-js-1kb.js
Format	JS (JavaScript source file)
Extension	.js
MIME type	text/javascript
Size	1,024 bytes (1 KB)
Kind	Text
SHA-256	a38f60e8a19b500b47463c4f21707d36ad7f62106284289cbebd64167a353598
Created	2026-10-10
Validation	Exact size, signature bytes and structure checked when the file was generated
Preview	Available on this page
Source	Generated for this site; not copied from elsewhere
Licence	Free to use, modify and redistribute (terms)
Category	Code

Validated for expected format and integrity. As with any download, scan the file with your own security tools before opening it. How files are made and checked

Download from the command line and verify

Fetch the file with curl, then compare its checksum with the SHA-256 value above.

curl -o sample-js-1kb.js 'https://sampletestfiles.com/downloads/js/sample-js-1kb.js'
sha256sum sample-js-1kb.js     # Linux
shasum -a 256 sample-js-1kb.js # macOS

On Windows, run Get-FileHash sample-js-1kb.js -Algorithm SHA256 in PowerShell. A matching value proves that the download is complete and unaltered.

Related files

Questions about this file

Is this file exactly 1 KB?: Yes. It is 1,024 bytes, which is 1 KB in the binary units that operating systems and server limits use (1 KB = 1,024 bytes).
What is inside the 1 KB JS file?: A "records" array of 4 object literals and two small helper functions. Line comments at the end bring the script to the exact size.
Does the sample script do anything when loaded?: No. It defines an array and two functions and has no side effects.

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