RTCRtpSender.getCapabilities.ts

// @ts-ignore
const { audioCodecs, videoCodecs } = args;

if ('RTCRtpSender' in self && RTCRtpSender.prototype) {
  proxyFunction(RTCRtpSender, 'getCapabilities', function (target, thisArg, argArray) {
    const kind = argArray && argArray.length ? argArray[0] : null;
    const args = kind ? [kind] : undefined;
    const capabilities = target.apply(thisArg, args);
    if (kind === 'audio') capabilities.codecs = audioCodecs;
    if (kind === 'video') capabilities.codecs = videoCodecs;
    return capabilities;
  });
}