ng build error - Property 'requestMIDIAccess' does not exist

Question

I am trying to build an Angular2 project, using the Web Midi API.

When runningng build, I am not able to complete the process due to certain errors thrown, specifically:

Error in bail mode: [default] /Users/JmsToh/GitHub/web-editor/web-editor/src/app/midi.service.ts:43:22 
Property 'requestMIDIAccess' does not exist on type 'Navigator'.

This comes from this part of the code:

if (navigator.requestMIDIAccess) {
  this.browserMidiCompatible = true;
  navigator.requestMIDIAccess({ sysex: false })
    .then(this.onMIDISuccess.bind(this), this.onMIDIReject.bind(this));
} else {
  alert("Platform not compatible");
}

The app runs fine on Chrome when running ng serve.Is there any way to get Angular2 to ignore the error when building?

Answer 1

Add the necessary type definitions using:

npm install @types/webmidi

They should be automatically discovered after restarting tsc.

note: If after installing the library you see errors "Cannot find name Map", see this answer.