iterate.js
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/** @license MIT License (c) copyright 2010-2014 original author or authors */
/** @author Brian Cavalier */
/** @author John Hann */
(function(define) { 'use strict';
define(function() {
return function generate(Promise) {
var resolve = Promise.resolve;
Promise.iterate = iterate;
Promise.unfold = unfold;
return Promise;
/**
* @deprecated Use github.com/cujojs/most streams and most.iterate
* Generate a (potentially infinite) stream of promised values:
* x, f(x), f(f(x)), etc. until condition(x) returns true
* @param {function} f function to generate a new x from the previous x
* @param {function} condition function that, given the current x, returns
* truthy when the iterate should stop
* @param {function} handler function to handle the value produced by f
* @param {*|Promise} x starting value, may be a promise
* @return {Promise} the result of the last call to f before
* condition returns true
*/
function iterate(f, condition, handler, x) {
return unfold(function(x) {
return [x, f(x)];
}, condition, handler, x);
}
/**
* @deprecated Use github.com/cujojs/most streams and most.unfold
* Generate a (potentially infinite) stream of promised values
* by applying handler(generator(seed)) iteratively until
* condition(seed) returns true.
* @param {function} unspool function that generates a [value, newSeed]
* given a seed.
* @param {function} condition function that, given the current seed, returns
* truthy when the unfold should stop
* @param {function} handler function to handle the value produced by unspool
* @param x {*|Promise} starting value, may be a promise
* @return {Promise} the result of the last value produced by unspool before
* condition returns true
*/
function unfold(unspool, condition, handler, x) {
return resolve(x).then(function(seed) {
return resolve(condition(seed)).then(function(done) {
return done ? seed : resolve(unspool(seed)).spread(next);
});
});
function next(item, newSeed) {
return resolve(handler(item)).then(function() {
return unfold(unspool, condition, handler, newSeed);
});
}
}
};
});
}(typeof define === 'function' && define.amd ? define : function(factory) { module.exports = factory(); }));