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- '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');
- * }
- */
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