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authorHubert Argasinski <argasinski.hubert@gmail.com>2016-03-31 02:22:16 -0700
committerGraeme Yeates <yeatesgraeme@gmail.com>2016-04-12 18:46:28 -0400
commit8eb2a7cec2c62edf35d7b812765bd64e6b7d484f (patch)
tree76a0c7715c612acddd9e6801dc14ec43f768176f /lib/waterfall.js
parenta778ee63788d533111ff63b611cc5034e18a907f (diff)
downloadasync-8eb2a7cec2c62edf35d7b812765bd64e6b7d484f.tar.gz
jsdoc-style documentation began documenting `Control Flow` methods
remaining `Control Flow` methods to document: - queue - priorityQueue - cargo - auto - autoInject - retry - retryable - iterator - times, timesSeries, timesLimit - race
Diffstat (limited to 'lib/waterfall.js')
-rw-r--r--lib/waterfall.js55
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diff --git a/lib/waterfall.js b/lib/waterfall.js
index aaed2ee..c76b332 100644
--- a/lib/waterfall.js
+++ b/lib/waterfall.js
@@ -7,6 +7,61 @@ import rest from 'lodash/rest';
import onlyOnce from './internal/onlyOnce';
+/**
+ * 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 async
+ * @category Control Flow
+ * @param {Array} tasks - An array of functions to run, each function is passed
+ * a `callback(err, result1, result2, ...)` it must call on completion. The
+ * first argument is an error (which can be `null`) and any further arguments
+ * 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]).
+ * @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');
+ * }
+ */
export default function(tasks, cb) {
cb = once(cb || noop);
if (!isArray(tasks)) return cb(new Error('First argument to waterfall must be an array of functions'));