While loop using bluebird promises

前端 未结 2 766
灰色年华
灰色年华 2020-11-27 19:09

I am trying to implement a while loop using promises.

The method outlined here seems to work. http://blog.victorquinn.com/javascript-promise-while-loop it uses a fun

2条回答
  •  广开言路
    2020-11-27 19:35

    cast can be translated to resolve. defer should indeed not be used.

    You'd create your loop only by chaining and nesting then invocations onto an initial Promise.resolve(undefined).

    function promiseWhile(predicate, action, value) {
        return Promise.resolve(value).then(predicate).then(function(condition) {
            if (condition)
                return promiseWhile(predicate, action, action());
        });
    }
    

    Here, both predicate and action may return promises. For similar implementations also have a look at Correct way to write loops for promise. Closer to your original function would be

    function promiseWhile(predicate, action) {
        function loop() {
            if (!predicate()) return;
            return Promise.resolve(action()).then(loop);
        }
        return Promise.resolve().then(loop);
    }
    

提交回复
热议问题