delucisfontace
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 informat(), e.g."woff2"or"truetype".isVariable:trueif 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 tounicodeRange.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 fontkit package to extract data from font files.