91 lines
		
	
	
		
			2.9 KiB
		
	
	
	
		
			JavaScript
		
	
	
	
	
	
			
		
		
	
	
			91 lines
		
	
	
		
			2.9 KiB
		
	
	
	
		
			JavaScript
		
	
	
	
	
	
'use strict';
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Object.defineProperty(exports, "__esModule", {
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    value: true
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});
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exports.default = seq;
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var _noop = require('lodash/noop');
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var _noop2 = _interopRequireDefault(_noop);
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var _slice = require('./internal/slice');
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var _slice2 = _interopRequireDefault(_slice);
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var _reduce = require('./reduce');
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var _reduce2 = _interopRequireDefault(_reduce);
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var _wrapAsync = require('./internal/wrapAsync');
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var _wrapAsync2 = _interopRequireDefault(_wrapAsync);
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var _arrayMap = require('lodash/_arrayMap');
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var _arrayMap2 = _interopRequireDefault(_arrayMap);
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function _interopRequireDefault(obj) { return obj && obj.__esModule ? obj : { default: obj }; }
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/**
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 * Version of the compose function that is more natural to read. Each function
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 * consumes the return value of the previous function. It is the equivalent of
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 * [compose]{@link module:ControlFlow.compose} with the arguments reversed.
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 *
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 * Each function is executed with the `this` binding of the composed function.
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 *
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 * @name seq
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 * @static
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 * @memberOf module:ControlFlow
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 * @method
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 * @see [async.compose]{@link module:ControlFlow.compose}
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 * @category Control Flow
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 * @param {...AsyncFunction} functions - the asynchronous functions to compose
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 * @returns {Function} a function that composes the `functions` in order
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 * @example
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 *
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 * // Requires lodash (or underscore), express3 and dresende's orm2.
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 * // Part of an app, that fetches cats of the logged user.
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 * // This example uses `seq` function to avoid overnesting and error
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 * // handling clutter.
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 * app.get('/cats', function(request, response) {
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 *     var User = request.models.User;
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 *     async.seq(
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 *         _.bind(User.get, User),  // 'User.get' has signature (id, callback(err, data))
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 *         function(user, fn) {
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 *             user.getCats(fn);      // 'getCats' has signature (callback(err, data))
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 *         }
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 *     )(req.session.user_id, function (err, cats) {
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 *         if (err) {
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 *             console.error(err);
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 *             response.json({ status: 'error', message: err.message });
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 *         } else {
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 *             response.json({ status: 'ok', message: 'Cats found', data: cats });
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 *         }
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 *     });
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 * });
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 */
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function seq() /*...functions*/{
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    var _functions = (0, _arrayMap2.default)(arguments, _wrapAsync2.default);
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    return function () /*...args*/{
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        var args = (0, _slice2.default)(arguments);
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        var that = this;
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        var cb = args[args.length - 1];
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        if (typeof cb == 'function') {
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            args.pop();
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        } else {
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            cb = _noop2.default;
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        }
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        (0, _reduce2.default)(_functions, args, function (newargs, fn, cb) {
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            fn.apply(that, newargs.concat(function (err /*, ...nextargs*/) {
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                var nextargs = (0, _slice2.default)(arguments, 1);
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                cb(err, nextargs);
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            }));
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        }, function (err, results) {
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            cb.apply(that, [err].concat(results));
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        });
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    };
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}
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module.exports = exports['default']; |