tingyuan lovetingyuan

This for loop:

for (let i = 0, getI = () => i; i < 3; i++)
  console.log(getI());

unrolls to:

	function resolveValue (promise, value, resolve, reject) {
	if (promise === value) { // 不能resolve自身
	return reject(new TypeError('Can not resolve or return the current promise.'))
	}
	if (value === null \|\| (typeof value !== 'object' && typeof value !== 'function')) {
	return resolve(value)
	}
	let then // thenable可能是对象或者函数，它的then只能读取一次并且需要捕获可能的错误
	try {
	then = value.then