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Diffstat (limited to 'lib/seq.js')
-rw-r--r-- | lib/seq.js | 36 |
1 files changed, 36 insertions, 0 deletions
@@ -4,6 +4,42 @@ import noop from 'lodash/noop'; import rest from 'lodash/rest'; import reduce from './reduce'; +/** + * Version of the compose function that is more natural to read. Each function + * consumes the return value of the previous function. It is the equivalent of + * [`compose`](#compose) with the arguments reversed. + * + * Each function is executed with the `this` binding of the composed function. + * + * @name seq + * @static + * @memberOf async + * @see `async.compose` + * @category Control Flow + * @param {...Function} functions - the asynchronous functions to compose + * @example + * + * // Requires lodash (or underscore), express3 and dresende's orm2. + * // Part of an app, that fetches cats of the logged user. + * // This example uses `seq` function to avoid overnesting and error + * // handling clutter. + * app.get('/cats', function(request, response) { + * var User = request.models.User; + * async.seq( + * _.bind(User.get, User), // 'User.get' has signature (id, callback(err, data)) + * function(user, fn) { + * user.getCats(fn); // 'getCats' has signature (callback(err, data)) + * } + * )(req.session.user_id, function (err, cats) { + * if (err) { + * console.error(err); + * response.json({ status: 'error', message: err.message }); + * } else { + * response.json({ status: 'ok', message: 'Cats found', data: cats }); + * } + * }); + * }); + */ export default function seq( /* functions... */ ) { var fns = arguments; return rest(function(args) { |