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window: queryLocalFonts() method

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

The window.queryLocalFonts() method returns a Promise that fulfills with an array of FontData objects representing the font faces available locally.

To use this method, the user must grant permission to access 'local-fonts' (permission status can be queried via the Permissions API). In addition, this feature may be blocked by a Permissions Policy set on your server.

Syntax

queryLocalFonts(options)

Parameters

options Optional

Contains optional configuration parameters. Currently only one property is defined:

postscriptNames: An array of font PostScript names. If this is specified, only fonts with PostScript names matching those in the array will be included in the results.

Return value

A Promise that fulfills with an array of FontData objects representing the font faces available locally.

Exceptions

NotAllowedError DOMException: The user chose to deny permission to use this feature when presented with the browser's permission prompt after the method was first invoked.
SecurityError DOMException: Use of this feature was blocked by a Permissions Policy, or it was not called via a user interaction such as a button press.

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);
  }
}

Limiting returned results

To limit the returned font data to only a specific list of font faces, use the postscriptNames option.

async function returnSpecificFonts() {
  const availableFonts = await window.queryLocalFonts({
    postscriptNames: ["Verdana", "Verdana-Bold", "Verdana-Italic"],
  });

  return availableFonts;
}

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 # dom-window-querylocalfonts

Browser compatibility

	Desktop						Mobile
	Chrome	Edge	Firefox	Internet Explorer	Opera	Safari	WebView Android	Chrome Android	Firefox for Android	Opera Android	Safari on IOS	Samsung Internet
`queryLocalFonts`	103	103	No	No	No	No	No	No	No	No	No	No