fontace

fontace

Extract useful information from font files

Installation

npm install fontace

Import

import { fontace } from 'fontace';

Why fontace?

fontace is a small library, which intends to extract data specifically to help generate CSS @font-face declarations based on font files.

fontace returns the following CSS-compatible values intended for use with font-family, font-style, unicode-range, and font-weight:

• family: The font family name as stored in the font file, e.g. "Inter".
• style: The style of this font file, e.g. "normal" or "italic".
• unicodeRange: The range of Unicode code points this font file contains, e.g. "U+0-10FFFF".
• weight: The font weight(s) this file supports, which can be a range for variable fonts, e.g. "400" or "100 900".

In addition it returns:

• format: The font file format for use in format(), e.g."woff2" or "truetype".
• isVariable: true if the font file contains variable axes of some kind.
• unicodeRangeArray: An array of the Unicode code point ranges this font file contains, e.g. ["U+0-10FFFF"], equivalent to unicodeRange.split(', '). Useful if you need to iterate through the available ranges instead of inlining them directly in CSS.

Usage

Pass a buffer containing font file data to fontace() and get useful information back.

Example: local font file

Use file-system APIs to read a local font file and then pass it to fontace():

import { fontace } from 'fontace';
import fs from 'node:fs';

const fontBuffer = fs.readFileSync('./Inter.woff2');
const metadata = fontace(fontBuffer);
// { family: "Inter", format: 'woff2', style: "normal", weight: "400", isVariable: false, unicodeRange: "U+0, U+20-7E...", unicodeRangeArray: ["U+0", "U+20-7E", ...] }

Example: remote font file

Fetch a font file over the network and then pass it to fontace():

import { fontace } from 'fontace';

const response = await fetch('https://example.com/Inter-Variable.woff2');
const fontBuffer = Buffer.from(await response.arrayBuffer());
const metadata = fontace(fontBuffer);
// { family: "Inter", format: 'woff2', style: "normal", weight: "100 900", isVariable: true, unicodeRange: "U+0, U+20-7E...", unicodeRangeArray: ["U+0", "U+20-7E", ...] }

Example: using fontace data to create CSS

const { family, format, isVariable, style, unicodeRange, weight } = fontace(fontBuffer);

let src = `url(/MyFont.woff2) format('${format}')`;
if (isVariable) src += ' tech(variations)';

const fontFaceDeclaration = `@font-face {
  font-family: ${family};
  font-style: ${style};
  font-weight: ${weight};
  font-display: swap;
  unicode-range: ${unicodeRange};
  src: ${src};
}`;

Acknowledgements

fontace uses the fontkitten package to extract data from font files.

License

MIT