web api instance method
Window: queryLocalFonts() method
Limited availabilitySecure context
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
optionsOptional- : Contains optional configuration parameters. Currently only one property is defined:
postscriptNamesOptional- : 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; if not, all fonts will be included in the results.
- : Contains optional configuration parameters. Currently only one property is defined:
Return value
A Promise that fulfills with an array of FontData objects representing the font faces available locally.
Exceptions
NotAllowedErrorDOMException- : The user chose to deny permission to use this feature when presented with the browser’s permission prompt after the method was first invoked.
SecurityErrorDOMException- : Use of this feature was blocked by a Permissions Policy, or it was not called via a user interaction such as a button press, or current origin is an opaque origin.
Examples
For a working live demo, see our Local Font Access API 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://learn.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);
}
}