easy-loop
Version:
Easy sync loop processing for Node.js
100 lines (98 loc) • 2.21 kB
JavaScript
;
function easyFor(obj, func, concurrency, last){
var max = 0;
var argsLen = arguments.length;
var isArr = obj instanceof Array;
var isNum = false;
var keys = null;
var isEnd = false;
var isWaterfall = (func === undefined || typeof func === 'function') && isWaterfallCall(obj);
if(obj instanceof Array) max = obj.length;
else if(obj instanceof Object)
{
keys = Object.keys(obj);
max = keys.length;
}
else if(typeof obj === 'number' && obj >= 0)
{
isNum = true;
max = obj;
}
else throw "first argument is not Array or Object or number of iterations => " + obj;
if((argsLen === 3 || argsLen === 4) && typeof func === 'number' && typeof concurrency === 'function')
{
var temp = func;
func = concurrency;
concurrency = temp;
}
if(typeof concurrency === 'function')
{
last = concurrency;
concurrency = 1;
}
else
{
if(!concurrency || isNaN(concurrency)) concurrency = 1;
else concurrency = parseInt(concurrency);
}
if(isWaterfall && typeof func === 'function')
{
last = func;
func = null;
}
var count = {start:0, end:0, processing:0};
var next = function(err){
count.processing--;
count.end++;
if(count.end >= max || err)
{
if(last && !isEnd)
{
if(err) last(err);
else
{
if(isWaterfall) last.apply(this, Array.from(arguments));
else last();
}
}
isEnd = true;
}
else
{
if(isWaterfall) run.apply(this, Array.prototype.slice.call(arguments, 1));
else run();
}
};
var run = function(){
if(max > count.start)
{
count.processing++;
if(isArr)
{
if(isWaterfall) obj[count.start++].apply(this, Array.from(arguments).concat(next));
else func(count.start, obj[count.start++], next);
}
else if(isNum) func(count.start++, next);
else func(keys[count.start], obj[keys[count.start++]], next);
if(max > count.start && count.processing < concurrency) run();
}
};
max == 0 ? next() : run();
}
function isWaterfallCall(arr){
var result = arr instanceof Array;
if(result)
{
if(arr.length === 0) result = false;
for(var a of arr)
{
if(typeof a !== 'function')
{
result = false;
break;
}
}
}
return result;
}
module.exports = easyFor;