Linq for javascript
This script should not be not be installed directly. It is a library for other scripts to include with the meta directive // @require https://update.greasyfork.org/scripts/376052/690663/LINQ.js
// ==UserScript==
// @name LINQ
// @namespace http://tampermonkey.net/
// @version 0.3
// @description Linq for javascript
// @author You
// @grant none
// ==/UserScript==
class Enumerable{
constructor(iterable,isClosure=true){
this.iterable=isClosure?iterable():iterable;
this.extends=[];
}
*[Symbol.iterator](){
let cache=[];
for(let x of this.iterable){
cache.push(x);
yield x;
}
for(let x of this.extends){
cache.push(x);
yield x;
}
this.iterable=cache;
}
compare(a,b){
a=a+"";
b=b+"";
let al=a.length;
let bl=b.length;
let n=al>bl?al:bl;
for (let i=0;i<n;i++){
if (i<al && i<bl){
if (a.charCodeAt(i)>b.charCodeAt(i)){
return 1;
}
else if (a.charCodeAt(i)<b.charCodeAt(i)){
return -1;
}
}
}
if (al>bl){
return 1;
}
else if (al<bl){
return -1;
}
return 0;
}
orderBy(selector){
let sorted=this.toArray().sort((a,b)=>this.compare(selector(a),selector(b)));
return new Enumerable(sorted,false);
}
orderByDescending(selector){
let sorted=this.toArray().sort((a,b)=>this.compare(selector(b),selector(a)));
return new Enumerable(sorted,false);
}
where(predicate){
let a=this;
return new Enumerable(function*(){
for (let x of a){
if (predicate(a)){
yield x;
}
}
});
}
count(predicate){
predicate=predicate || function(){return true;};
let count=0;
for(let x of this){
if (predicate(x)){
count+=1;
}
}
return count;
}
first(predicate){
predicate=predicate || function(){return true;};
for(let x of this){
if (predicate(x)){
return x;
}
}
throw "Sequence least than 1";
}
firstOrDefault(predicate){
try {
return this.first(predicate);
}
catch(e){
return null;
}
}
elementAt(n){
let id=0;
for (let x of this){
if (id==n){
return x;
}
id++;
}
throw "Index of found";
}
select(selector){
let a=this;
return new Enumerable(function*(){
for(let x of a){
yield selector(x);
}
});
}
join(object,outerSelector,innerSelector,selector){
let a=this;
return new Enumerable(function*(){
for(let x of a){
for(let y of object){
if (outerSelector(x)==innerSelector(y)){
yield selector(x,y);
}
}
}
});
}
groupBy(selector){
let sorted=this.orderBy(selector);
return new Enumerable(function(){
let isSetInit=false;
let key=null;
let temp=null;
let result=[];
for(let x of sorted){
if (!isSetInit){
key=selector(x);
temp=new Grouping(key,[]);
isSetInit=true;
}
else{
if (selector(x)==key){
temp.append(x);
}
else{
key=selector(x);
result.push(temp);
temp=new Grouping(key,[]);
}
}
}
result.push(temp);
return result;
});
}
distinct(selector){
return this.groupBy(selector).select(x=>x.first());
}
toEnumerable(){
return new Enumerable(this,false);
}
toArray(){
let result=[];
for(let x of this){
result.push(x);
}
return result;
}
each(action){
for (let x of this){
action(x);
}
}
aggregate(func,initValue=null){
let isSetInit=false;
let accu=null;
if (initValue!=null){
accu=initValue;
isSetInit=false;
}
for (let x of this){
if (!isSetInit && accu==null){
accu=x;
continue;
}
accu=func(accu,x);
}
if (accu==null){
throw "Sequence less than 1";
}
return accu;
}
sum(selector){
selector=selector || function(x){return x;};
return this.select(selector).aggregate(function(accu,next){return accu+next;},0);
}
max(selector){
selector=selector || function(x){return x;};
return this.select(selector).aggregate(function(accu,next){return accu>next?accu:next;});
}
min(selector){
selector=selector || function(x){return x;};
return this.select(selector).aggregate(function(accu,next){return accu<next?accu:next;});
}
unique(selector){
return this.groupBy(selector).select(function(x){return x.first();});
}
selectMany(collectionSelect=null,resultSelect=null){
collectionSelect=collectionSelect || function(x){return x};
resultSelect=resultSelect || function(x,y){return y;};
let a=this;
return new Enumerable(function*(){
for(let x of a.select(collectionSelect)){
for(let y of x){
yield resultSelect(x,y);
}
}
});
}
static from(iterable){
return new Enumerable(iterable,false);
}
static range(from,to){
return new Enumerable(function*(){
for(let i=from;i<to;i++){
yield i;
}
});
}
static repeat(object,count){
return new Enumerable(function*(){
for(let i=0;i<count;i++){
yield object;
}
});
}
append(object){
this.extends.push(object);
}
}
class Grouping extends Enumerable {
constructor(key, iterable) {
super(iterable,false);
this.key = key;
}
}