一、题目
题目：红灯三秒亮一次，绿灯两秒亮一次，黄灯一秒亮一次；如何让三个灯不断交替重复亮灯？
二、解决方案
思路：主要考察Promise
function red() {
console.log("red");
}
function green() {
console.log("green");
}
function yellow() {
console.log("yellow");
}
const sleep = (time, fn) => {
return new Promise((resolve) => {
setTimeout(() => {
fn(); //哪个灯亮
resolve();
}, time);
});
};
let step = () => {
Promise.resolve()
.then(() => {
return sleep(3000, red);
})
.then(() => {
return sleep(2000, green);
})
.then(() => {
return sleep(1000, yellow);
})
.then(() => {
step();
});
};
