Simple, isolated async waterfall module for JavaScript. Zero dependencies. Runs a list of tasks, passing the results of each into the next one.
MIT License
Simple, isolated async waterfall module for JavaScript.
Runs an array of functions in series, each passing their results to the next in the array. However, if any of the functions pass an error to the callback, the next function is not executed and the main callback is immediately called with the error.
For browsers and node.js.
npm install async-waterfall
if you’re using node.js.component install es128/async-waterfall
if you’re usingbower install async-waterfall
if you’re usingwaterfall(tasks, optionalCallback);
callback(err, result1, result2, ...)
it must call on completion. The firstvar waterfall = require('async-waterfall');
waterfall(tasks, callback);
// component(1)
var waterfall = require('async-waterfall');
waterfall(tasks, callback);
// Default:
window.asyncWaterfall(tasks, callback);
waterfall([
function(callback){
callback(null, 'one', 'two');
},
function(arg1, arg2, callback){
callback(null, 'three');
},
function(arg1, callback){
// arg1 now equals 'three'
callback(null, 'done');
}
], function (err, result) {
// result now equals 'done'
});
/* basic - no arguments */
waterfall(myArray.map(function (arrayItem) {
return function (nextCallback) {
// same execution for each item, call the next one when done
doAsyncThingsWith(arrayItem, nextCallback);
}}));
/* with arguments, initializer function, and final callback */
waterfall([function initializer (firstMapFunction) {
firstMapFunction(null, initialValue);
}].concat(myArray.map(function (arrayItem) {
return function (lastItemResult, nextCallback) {
// same execution for each item in the array
var itemResult = doThingsWith(arrayItem, lastItemResult);
// results carried along from each to the next
nextCallback(null, itemResult);
}})), function (err, finalResult) {
// final callback
});
Hat tip to Caolan McMahon and Paul Miller, whose prior contributions this is based upon.