What it does
fonteditor-core reads, converts and edits font data inside JavaScript applications. The MIT-licensed library supports Node.js and browser use, including glyph operations and webfont output.
Format support is asymmetric: OTF files can be read and converted to TTF, but the library does not write OTF directly. TTF, WOFF, WOFF2, EOT and SVG have read-and-write support. Select the required output before assuming a conversion will preserve the original format.
The basic workflow is to read a font buffer with createFont, set the input type and options, then use font.write to produce a new buffer. Glyph lookup can use Unicode values or a custom filter; other methods optimize, sort, transform or merge glyph data. Enable hinting and kerning explicitly when reading and writing if you need to retain those tables.
WOFF2 needs the supplied WebAssembly module initialized before conversion. In Node.js, wait for woff2.init to finish; in a browser, provide the path to the WASM resource. Both CommonJS and ES module integration are supported. The library’s free licence does not grant rights to modify someone else’s font files.
Strengths
- Glyph lookup, transformation, sorting and merging are exposed through JavaScript.
- CommonJS, ES modules and TypeScript definitions are supported.
Watch out for
- OTF support does not include direct OTF writing.
- WOFF2 needs WebAssembly initialization; hinting and kerning are opt-in.
Best for
- Developers building font-processing utilities
Sources
- fonteditor-core README (Oct 27, 2026)
- fonteditor-core MIT License (Oct 27, 2026)