jquery - NodeJS 循环等待回调

Question

如何在 for 循环中等待，直到收到回调，然后继续 for 循环？

这是我的循环:

for(var i = 0; i < offer.items_to_receive.length; i++) {
    console.log("Waiting for callback...");
    doSomething(function(data) {
        console.log("Got data from callback! "  + data);
    });
    console.log("Continue for loop now.");
}

感谢您的投入!

Answer 1

如果调用的方法是异步的，您可能无法使用循环，而是可以使用基于递归的解决方案，例如

function x(items, i) {
  i = i || 0;
  if (i >= items.length) {
    return
  }
  snippet.log("Waiting for callback..." + i);
  doSomething(function(data) {
    snippet.log("Got data from callback! " + data);

    if (i == items.length - 1) {
      snippet.log("completed");
    } else {
      x(items, i + 1)
    }
  });
}

// a sample implementation of asynchronous method
var counter = 0;
function doSomething(cb) {
  setTimeout(cb.bind(window, counter++), 100)
}

x([1, 2, 3, 4])

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