The ready read-only property of the FontFaceSet interface returns a Promise that resolves to the given FontFaceSet.

The promise will only resolve once the document has completed loading fonts, layout operations are completed, and no further font loads are needed.

A Promise that resolves to the given FontFaceSet.

In the following example the value of ready is printed to the console once the promise has resolved.

async function isReady() {
  let ready = await document.fonts.ready;
  console.log(ready);
}

isReady();