SOURCE

//Generator函数定义及使用
function* gen() {
    yield 1;
    yield 2;
    return 3;
}
var g = gen();
console.log('还未执行');
for (let item of g) {
    console.log(item);
}
console.log('已经执行');

//使用Generator遍历多维数组
console.log('=======================')
var arr = [1, [[2, 3], 4], [5, 6]];
var flat = function* (arr) {
    for (let item of arr) {
        if (typeof item != 'number') {
            yield* flat(item);
        } else {
            yield item;
        }
    }
}
for (let item of flat(arr)) {
    console.log(item);
}

//使用常规方法遍历多维数组
console.log('=======================')
function flat2(arr) {
    var result = [];
    for (let item of arr) {
        if (typeof item != 'number') {
            flat2(item).forEach(childItem => {
                result.push(childItem);
            })
        } else {
            result.push(item);
        }
    }
    return result;
}
for (let item of flat2(arr)) {
    console.log(item);
}

//next方法带参数
//yield表达式本身没有返回值，或者说总是返回undefined。
//next方法可以带一个参数，该参数就会被当作上一个yield表达式的返回值。
console.log('=======================')
function* f() {
  for(var i = 0; true; i++) {
    var reset = yield i;
    if(reset) { i = -1; }
  }
}
var g = f();
console.log(g.next().value)
console.log(g.next().value) 
console.log(g.next(true).value)

//Generation内部调用另外一个Generation
console.log('=======================')
function* foo() {
    yield 'a';
    yield 'b';
}
function* bar() {
    yield 1;
    for (let f of foo()) {
        yield f;
    }
    yield 2;
}
var b = bar();
for (let item of b) {
    console.log(item);
}
//Thunk与Generation流程自动管理
console.log('=======================')
var Thunk = function(fn){
	return function(...args){
		return function(callback){
			fn.call(this,...args,callback);
		}
	}
};

var Calculate  = function(a,b,cb){
	var sum = a + b;
	cb(sum);
};

var ThunkCalculate = Thunk(Calculate);

var gen = function* (){
	var r1 = yield ThunkCalculate(1,2);
	console.log(r1);
	var r2 = yield ThunkCalculate(3,4);
	console.log(r2);
	var r3 = yield ThunkCalculate(5,6);
	console.log(r3);
};

var run = function(genFn){
	var g = genFn();
	var next = function(data){
		var result = g.next(data);
		if(result.done) return;
		result.value(next);
	}
	next();
};

run(gen);