size-satisfies

size-satisfies

Check whether a file size satisfies a given constraint — like semver.satisfies but for bytes.

Requirements

• Node.js v18 or higher

Getting Started

This package is available in the Node Package Repository and can be easily installed with npm or yarn.

$ npm i @nodesecure/size-satisfies
# or
$ yarn add @nodesecure/size-satisfies

Usage example

import sizeSatisfies from "@nodesecure/size-satisfies";

// String sizes are parsed using the `bytes` package (B, KB, MB, GB, …)
console.log(sizeSatisfies(">= 45KB", "20MB")); // true  — 20 MB is >= 45 KB
console.log(sizeSatisfies("<= 45KB", "10B"));  // true  — 10 B is <= 45 KB
console.log(sizeSatisfies("= 1MB", "1MB"));    // true  — exact match
console.log(sizeSatisfies("> 45KB", "45KB"));  // false — not strictly greater

// Numeric sizes are treated as bytes
console.log(sizeSatisfies(">= 45KB", 46080));  // true  — 46 080 B == 45 KB
console.log(sizeSatisfies("= 45KB", 2000));    // false — 2 000 B != 45 KB
console.log(sizeSatisfies("< 45KB", 0));       // true  — 0 B < 45 KB

// Invalid patterns always return false
console.log(sizeSatisfies("", "45KB"));        // false — empty pattern
console.log(sizeSatisfies("45KB", "45KB"));    // false — missing operator
console.log(sizeSatisfies("!! 45KB", "45KB")); // false — unknown operator

// Unparseable sizes fall back to 0
console.log(sizeSatisfies("> 0KB", "not_a_size"));   // false — 0 > 0 is false
console.log(sizeSatisfies("= 0KB", "not_a_size"));   // true  — 0 == 0
console.log(sizeSatisfies(">= not_a_size", "10KB")); // true  — 10 KB >= 0

API

sizeSatisfies(pattern, size)

function sizeSatisfies(pattern: string, size: number | string): boolean

Returns true when size satisfies the constraint expressed by pattern, false otherwise.

pattern

A string composed of an operator followed by a size value (with an optional space between them):

">= 45KB"
"<  1MB"
"=  512B"

Operator	Meaning
>=	greater than or equal to
<=	less than or equal to
>	strictly greater than
<	strictly less than
=	exactly equal to

The size value in the pattern is parsed by the bytes package and therefore supports the same units: B, KB, MB, GB, TB, PB (case-insensitive). An unparseable size value falls back to 0.

A pattern that is empty, has no operator, or uses an unrecognised operator causes the function to return false immediately.

size

The actual size to test against the pattern.

• number — interpreted as a raw byte count.
• string — parsed by the bytes package (e.g. "45KB", "1.5MB"). An unparseable string falls back to 0.

License

MIT