async.js waterfall 사용방법

ajax 콜을 여러번 시리얼하게 요청 하고자 한다면... 아래의 async waterfall 을 사용하길 추천 합니다...

Project : https://github.com/caolan/async

Guide: http://hatemogi.com/holiday-project-day-10/

waterfall(tasks, [callback])

Runs the tasks array of functions in series, each passing their results to the next in the array. However, if any of the tasks pass an error to their own callback, the next function is not executed, and the main callback is immediately called with the error.

Arguments

• tasks - An array of functions to run, each function is passed a callback(err, result1, result2, ...) it must call on completion. The first argument is an error (which can be null) and any further arguments will be passed as arguments in order to the next task.
• callback(err, [results]) - An optional callback to run once all the functions have completed. This will be passed the results of the last task's callback.

Example

async.waterfall([
    function(callback) {
        callback(null, 'one', 'two');
    },
    function(arg1, arg2, callback) {
      // arg1 now equals 'one' and arg2 now equals 'two'
        callback(null, 'three');
    },
    function(arg1, callback) {
        // arg1 now equals 'three'
        callback(null, 'done');
    }
], function (err, result) {
    // result now equals 'done'
});

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