javascript - 无法同步功能

Question

我正在尝试同步地一一执行这些函数。

var subtasks = ['Site', 'Draw', 'Material', 'Conduction', 'Cable', 'Install', 'Foundation']

function clickMe() {
  return new Promise(resolve => {
    jQuery("#addtoptasksubmit").trigger("click"); // triggering the button click
    resolve("done click");
  });
}

function typeWord(word) {
  return new Promise(resolve => {
    jQuery("#todotask").val(word); // input
    resolve("done type");
  });
}

function createSubTask() {
  return new Promise(res => {
    jQuery('#todotask').focus();
    res("done")

  })
};

function startLoop(i) {
  new Promise(resolve => {
    var promise = createSubTask();
    promise.then(resolve => {
      var typePromise = typeWord(subtasks[i]);
      typePromise.then((resolve) => {
        var clickPromise = clickMe();
        clickPromise.then((resolve) => {
          console.log(resolve);
        });
      });
    });
  })
}

let i = 0;
let prom = startLoop(i);

prom.then((res) => {
  startLoop(i++);
})

代码无法正常工作，而且我想自动增加 i 。 For 循环没有出现。

我在 Chrome 上尝试过 for 循环和递归异步函数。

Answer 1

您的 startLoop(i) 函数不需要为新的 Promise() 调用提供 return 语句吗？我必须想象一下:

// prom = undefined as startLoop never returns anything
let prom = startLoop(i);

像这样更改您的代码:

// Current code from description
function startLoop(i) {
  new Promise(resolve => {

// Fixed code
function startLoop(i) {
  return new Promise(resolve => {