84 lines
1.6 KiB
JavaScript
84 lines
1.6 KiB
JavaScript
'use strict';
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var once = require('once');
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var helpers = require('./helpers');
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function map(values, iterator, options, done) {
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// Allow for options to not be specified
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if (typeof options === 'function') {
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done = options;
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options = {};
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}
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// Handle no callback case
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if (typeof done !== 'function') {
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done = helpers.noop;
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}
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done = once(done);
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// Will throw if non-object
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var keys = Object.keys(values);
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var length = keys.length;
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var count = length;
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var idx = 0;
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// Return the same type as passed in
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var results = helpers.initializeResults(values);
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var extensions = helpers.defaultExtensions(options);
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if (length === 0) {
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return done(null, results);
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}
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var maxConcurrent = length;
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if (options && options.concurrency) {
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maxConcurrent = options.concurrency;
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}
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var running = 0;
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var sync = false;
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kickoff();
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function kickoff() {
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if (sync) {
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return;
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}
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sync = true;
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while (running < maxConcurrent && idx < length) {
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var key = keys[idx];
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next(key);
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idx++;
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}
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sync = false;
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}
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function next(key) {
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running++;
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var value = values[key];
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var storage = extensions.create(value, key) || {};
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extensions.before(storage);
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iterator(value, key, once(handler));
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function handler(err, result) {
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running--;
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if (err) {
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extensions.error(err, storage);
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return done(err, results);
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}
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extensions.after(result, storage);
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results[key] = result;
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if (--count === 0) {
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done(err, results);
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} else {
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kickoff();
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}
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}
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}
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}
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module.exports = map;
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