blob: d547d6b1e44ee9a6bc308b5281207b8255868104 [file] [log] [blame]
'use strict';
Object.defineProperty(exports, "__esModule", {
value: true
});
exports.default = function (tasks, callback) {
callback = (0, _once2.default)(callback || _noop2.default);
if (!(0, _isArray2.default)(tasks)) return callback(new Error('First argument to waterfall must be an array of functions'));
if (!tasks.length) return callback();
var taskIndex = 0;
function nextTask(args) {
var task = (0, _wrapAsync2.default)(tasks[taskIndex++]);
args.push((0, _onlyOnce2.default)(next));
task.apply(null, args);
}
function next(err /*, ...args*/) {
if (err || taskIndex === tasks.length) {
return callback.apply(null, arguments);
}
nextTask((0, _slice2.default)(arguments, 1));
}
nextTask([]);
};
var _isArray = require('lodash/isArray');
var _isArray2 = _interopRequireDefault(_isArray);
var _noop = require('lodash/noop');
var _noop2 = _interopRequireDefault(_noop);
var _once = require('./internal/once');
var _once2 = _interopRequireDefault(_once);
var _slice = require('./internal/slice');
var _slice2 = _interopRequireDefault(_slice);
var _onlyOnce = require('./internal/onlyOnce');
var _onlyOnce2 = _interopRequireDefault(_onlyOnce);
var _wrapAsync = require('./internal/wrapAsync');
var _wrapAsync2 = _interopRequireDefault(_wrapAsync);
function _interopRequireDefault(obj) { return obj && obj.__esModule ? obj : { default: obj }; }
module.exports = exports['default'];
/**
* 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.
*
* @name waterfall
* @static
* @memberOf module:ControlFlow
* @method
* @category Control Flow
* @param {Array} tasks - An array of [async functions]{@link AsyncFunction}
* to run.
* Each function should complete with any number of `result` values.
* The `result` values will be passed as arguments, in order, to the next task.
* @param {Function} [callback] - An optional callback to run once all the
* functions have completed. This will be passed the results of the last task's
* callback. Invoked with (err, [results]).
* @returns undefined
* @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'
* });
*
* // Or, with named functions:
* async.waterfall([
* myFirstFunction,
* mySecondFunction,
* myLastFunction,
* ], function (err, result) {
* // result now equals 'done'
* });
* function myFirstFunction(callback) {
* callback(null, 'one', 'two');
* }
* function mySecondFunction(arg1, arg2, callback) {
* // arg1 now equals 'one' and arg2 now equals 'two'
* callback(null, 'three');
* }
* function myLastFunction(arg1, callback) {
* // arg1 now equals 'three'
* callback(null, 'done');
* }
*/