A script for running generator functions

runner.js

let runner = function (fn) {
    if (typeof fn !== 'function') {
        throw 'A generator function is expected';
    }

    var done = false;
    var gen = fn();
    var val;
    while (!done) {
        let obj = gen.next(val);
        done = obj.done;
        val = obj.value;
    }
};

usage.js

var doStuff = function* () {
    console.log(+new Date);
    let x = yield go();
    console.log('yeaaaaaaah', x);

    let y = yield go();
    console.log('yeaaaaaaah', y);
    console.log(+new Date);
};

var go = function () {
    for (let i = 0; i < 10000000; i++) {
        //
    }

    return 'foo';
};

runner(doStuff);