You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
56 lines
980 B
56 lines
980 B
'use strict';
|
|
|
|
module.exports = parallelLimit;
|
|
|
|
/*!
|
|
* ignore
|
|
*/
|
|
|
|
function parallelLimit(fns, limit, callback) {
|
|
let numInProgress = 0;
|
|
let numFinished = 0;
|
|
let error = null;
|
|
|
|
if (limit <= 0) {
|
|
throw new Error('Limit must be positive');
|
|
}
|
|
|
|
if (fns.length === 0) {
|
|
return callback(null, []);
|
|
}
|
|
|
|
for (let i = 0; i < fns.length && i < limit; ++i) {
|
|
_start();
|
|
}
|
|
|
|
function _start() {
|
|
fns[numFinished + numInProgress](_done(numFinished + numInProgress));
|
|
++numInProgress;
|
|
}
|
|
|
|
const results = [];
|
|
|
|
function _done(index) {
|
|
return (err, res) => {
|
|
--numInProgress;
|
|
++numFinished;
|
|
|
|
if (error != null) {
|
|
return;
|
|
}
|
|
if (err != null) {
|
|
error = err;
|
|
return callback(error);
|
|
}
|
|
|
|
results[index] = res;
|
|
|
|
if (numFinished === fns.length) {
|
|
return callback(null, results);
|
|
} else if (numFinished + numInProgress < fns.length) {
|
|
_start();
|
|
}
|
|
};
|
|
}
|
|
}
|