63 lines
1.5 KiB
JavaScript
63 lines
1.5 KiB
JavaScript
var Q = require('q');
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var _ = require('lodash');
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// Reduce an array to a promise
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function reduce(arr, iter, base) {
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return _.reduce(arr, function(prev, elem, i) {
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return prev.then(function(val) {
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return iter(val, elem, i);
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});
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}, Q(base));
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}
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// Transform an array
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function serie(arr, iter, base) {
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return reduce(arr, function(before, item, i) {
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return Q(iter(item, i))
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.then(function(r) {
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before.push(r);
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return before;
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});
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}, []);
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}
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// Iter over an array and return first result (not null)
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function some(arr, iter) {
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return _.reduce(arr, function(prev, elem, i) {
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return prev.then(function(val) {
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if (val) return val;
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return iter(elem, i);
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});
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}, Q());
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}
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// Map an array using an async (promised) iterator
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function map(arr, iter) {
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return reduce(arr, function(prev, entry, i) {
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return Q(iter(entry, i))
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.then(function(out) {
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prev.push(out);
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return prev;
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});
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}, []);
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}
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// Wrap a fucntion in a promise
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function wrap(func) {
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return _.wrap(func, function(_func) {
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var args = Array.prototype.slice.call(arguments, 1);
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return Q()
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.then(function() {
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return _func.apply(null, args);
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});
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});
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}
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module.exports = Q;
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module.exports.reduce = reduce;
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module.exports.map = map;
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module.exports.serie = serie;
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module.exports.some = some;
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module.exports.wrapfn = wrap;
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