no-undef rule applies to Flow type annotations

In my codebase I have the lines:

  warnInProgressUpload(e: UnloadEvent) {
    if (!this.state.uploadingUploads.size) return undefined;
    var confirmationMessage = 'You have an upload in progress, if you leave the page your upload will be cancelled.';
    (e || window.event).returnValue = confirmationMessage;
    return confirmationMessage;
  }

UnloadEvent is a type declaration defined in a separate file

declare class UnloadEvent extends Event {
    returnValue: string;
}

This produces the error:

  107:27  error  "UnloadEvent" is not defined  no-undef

Can eslint skip running no-undef on type annotations?

[gibbok]

Check out eslint-plugin-flowtype: An eslint plugin that makes flow type annotations global variables and marks declarations as used. Solves the problem of false positives with no-undef and no-unused-vars.

[tmcw]

Ah thanks everyone!