FontData

Experimental: This is an experimental technology
Check the Browser compatibility table carefully before using this in production.

The FontData interface of the Local Font Access API represents a single local font face.

Instance properties

FontData.family Read only Experimental: Returns the family of the font face.
FontData.fullName Read only Experimental: Returns the full name of the font face.
FontData.postscriptName Read only Experimental: Returns the PostScript name of the font face.
FontData.style Read only Experimental: Returns the style of the font face.

Instance methods

FontData.blob() Read only Experimental: Returns a Promise that fulfills with a Blob containing the raw bytes of the underlying font file.

Examples

For a working live demo, see Font Select Demo.

Font enumeration

The following snippet will query for all available fonts, and log metadata. This could be used, for example, to populate a font-picker control.

async function logFontData() {
  try {
    const availableFonts = await window.queryLocalFonts();
    for (const fontData of availableFonts) {
      console.log(fontData.postscriptName);
      console.log(fontData.fullName);
      console.log(fontData.family);
      console.log(fontData.style);
    }
  } catch (err) {
    console.error(err.name, err.message);
  }
}

Accessing low-level data

The blob() method provides access to low-level SFNT data — this is a font file format that can contain other font formats, such as PostScript, TrueType, OpenType, or Web Open Font Format (WOFF).

async function computeOutlineFormat() {
  try {
    const availableFonts = await window.queryLocalFonts({
      postscriptNames: ["ComicSansMS"],
    });
    for (const fontData of availableFonts) {
      // `blob()` returns a Blob containing valid and complete
      // SFNT-wrapped font data.
      const sfnt = await fontData.blob();
      // Slice out only the bytes we need: the first 4 bytes are the SFNT
      // version info.
      // Spec: https://docs.microsoft.com/en-us/typography/opentype/spec/otff#organization-of-an-opentype-font
      const sfntVersion = await sfnt.slice(0, 4).text();

      let outlineFormat = "UNKNOWN";
      switch (sfntVersion) {
        case "\x00\x01\x00\x00":
        case "true":
        case "typ1":
          outlineFormat = "truetype";
          break;
        case "OTTO":
          outlineFormat = "cff";
          break;
      }
      console.log("Outline format:", outlineFormat);
    }
  } catch (err) {
    console.error(err.name, err.message);
  }
}

Specifications

Specification
Local Font Access # fontdata-interface

Browser compatibility

BCD tables only load in the browser