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