循环打印红绿黄

function red() {
    console.log('red');
}
function green() {
    console.log('green');
}
function yellow() {
    console.log('yellow');
}
function lightPromise(func, delay) {
    return new Promise((resolve, reject) => {
        setTimeout(() => {
            func();
            resolve();
        }, delay);
    })
}
function light() {
    Promise.resolve()
        .then(() => lightPromise(red, 3000))
        .then(() => lightPromise(green, 1000))
        .then(() => lightPromise(yellow, 2000))
        .then(light)
}
light();