Function check

static/word2md/mammoth.browser.js:6778–6785

(self, executor)

var errorObj = util.errorObj;
var tryCatch = util.tryCatch;
function check(self, executor) {
    if (typeof executor !== "function") {
        throw new TypeError("expecting a function but got " + util.classString(executor));
    }
    if (self.constructor !== Promise) {
        throw new TypeError("the promise constructor cannot be invoked directly\u000a\u000a    See http://goo.gl/MqrFmX\u000a");
    }
}

function Promise(executor) {
    this._bitField = 0;