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linq4js

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Linq4JS

Linq methods for JavaScript/TypeScript for working with Arrays

This simple Extension works with array of complex Objects as well as simple arrays of strings etc. The whole thing is written in TypeScript but also usable in JavaScript

Advantages

This Extension is lightweight and fast and you can use your Lambda-Expression-Syntax to work with Arrays. The methods are mostly identically to .NET methods.

As Expressions you can use the normal Function-Syntax:

array.Where(function(x){
    return x.Name == "Max";
});

Lambda-Expressions (IE isn't compatible with this Lambda-Expressions):

array.Where(x => x.Name == "Max");

or Lambda-Expressions as Strings (this Syntax works in IE):

array.Where("x => x.Name == 'Max'");

Conclusion:

Works with multiple Browsers (even IE)
Angular Support (event directly in Views if using Strings as Expression-Syntax)
Lightweight
Fast
Syntax from .NET

Getting Started

Install using NPM

npm install linq4js

Install using Bower

bower install linq4js

Using JavaScript

Include this Line in your Project

<script type="text/javascript" src="Linq4JS.js"></script>

Using TypeScript

Same thing, but also copy Linq4JS.d.ts to your project Folder to get the tooling support.

Usage

Clone

Create a copy of the array

var array = ["item1", "item2", "item3", "item4", "no"];

//["item1", "item2", "item3", "item4", "no"]
array.Clone();

FindIndex

Get the Index of the first item found by a filter

var array = ["item1", "item2", "item3", "item4", "no"];

//2
array.FindIndex("x => x == 'item3'");

Get

Gets the item with the index

var array = ["item1", "item2", "item3", "item4", "no"];

//"item3"
array.Get(2);

Repeat

Repeats an object in the array

var array = ["item1", "item2", "item3", "item4"];

//["item1", "item2", "item3", "item4", "example", "example", "example"]
array.Repeat("example", 3);

ForEach

Executes a method for each item in the array

var array = ["item1", "item2", "item3", "item4", "no"];
array.ForEach("i => console.log(i)");

Update & UpdateRange

Updates in Object in the array

By default this method uses the property Id to Identify the Objects. If The property is not set this methods tries to compare the objects directly.

var array = [{Id: 1, Value: "item1"}, {Id: 2, Value: "item2"}];
    
//[{Id: 1, Value: "item3"}, {Id: 2, Value: "item2"}]
array.Update({Id: 1, Value: "item3"});

If you want this method to use other Fields for Identification define a selector function as second parameter.

var array = [{OtherId: 1, Value: "item1"}, {OtherId: 2, Value: "item2"}];
    
//[{Id: 1, Value: "item3"}, {Id: 2, Value: "item2"}]
array.Update({OtherId: 1, Value: "item3"}, "x => x.OtherId");

You can upgrade multiple objects simultaneously

var array = [{OtherId: 1, Value: "item1"}, {OtherId: 2, Value: "item2"}];
    
//[{Id: 1, Value: "item3"}, {Id: 2, Value: "item4"}]
array.UpdateRange(
    [{OtherId: 1, Value: "item3"}, {OtherId: 2, Value: "item4"}], 
    "x => x.OtherId");

Remove & RemoveRange

Removes item(s) from array

By default this method uses the property Id to Identify the Objects. If The property is not set this methods tries to compare the objects directly.

var array = ["item1", "item2", "item3", "item4", "no"];

//["item1", "item2", "item3", "item4"]
array.Remove("no");
    
//["item1", "item2"]
array.RemoveRange(["item4", "item3"]);

If you want this method to use other Fields for Identification define a selector function as second parameter.

var array = [{OtherId: 1, Value: "item1"}, {OtherId: 2, Value: "item2"}];

//[{OtherId: 2, Value: "item2"}]
array.Remove({OtherId: 1}, "x => x.OtherId");

Add & AddRange

Adds the item(s) to the array

var array = ["item1", "item2", "item3", "item4", "no"];

//["item1", "item2", "item3", "item4", "no", "item5"]
array.Add("item5");

//["item1", "item2", "item3", "item4", "no", "item5", "item6", "item7"]
array.AddRange(["item6", "item7"]);

Insert

Inserts an entry at a specific position

var array = ["item1", "item2", "item3", "item4"];

//["item1", "item2", "item2.5", "item3", "item4"]
array.Insert("item2.5", 2);

Where

Search for all items in array that match the filter

var array = ["item1", "item2", "item3", "item4", "no"];

//["item1", "item2", "item3", "item4"]
array.Where("i => i.match(/item/gi)");

Range

Takes items in a specific range

var array = ["item1", "item2", "item3", "item4"];

//["item2", "item3"]
array.Range(1, 2);

Count

Returns the length of the array or if a filter is set the length of the resulting array

var array = ["item1", "item2", "item3", "item4", "no"];

//5
array.Count();

//4
array.Count("i => i.match(/item/gi)");

SequenceEqual

Compares to sequences of objects

var array = ["item1", "item2", "item3"];
var array2 = ["item1", "item2", "item3"];
var array3 = ["item", "item2", "item3"];

//true
array.SequenceEqual(array2);

//false
array.SequenceEqual(array3);

Any

Tests if any item is in the array and if set matches the filter

var array = ["item1", "item2", "item3", "item4", "no"];

//true
array.Any();

//true
array.Any("i => i.length > 2");
    
//false
array.Any("i => i == ''");

All

Tests if all items in the array match the condition

var array = ["item1", "item2", "item3", "item4", "no"];

//false
array.All("i => i.length > 2");

Contains

Tests if array contains specific object

var array = ["item1", "item2", "item3", "item4", "no"];

//false
array.Contains("test");

Concat

Combines two arrays

var array = ["item1", "item2", "item3"];
var array2 = ["item4", "no"];

//["item1", "item2", "item3", "item4", "no"]
array.Concat(array2);

Intersect

Combines two arrays but only applies values that are in both arrays

var array = ["item1", "item2", "item3"];
var array2 = ["item1", "unique", "item2", "item3"];

//["item1", "item2", "item3"]
array.Intersect(array2);

Union

Combines two arrays without duplicates

var array = ["item1", "item2", "item3"];
var array2 = ["item1", "unique", "item2", "item3"];

//["item1", "item2", "item3", "unique"]
array.Union(array2);

Join

Joins the entries by the given char

var array = ["item1", "item2", "item3", "item4", "no"];

//item1-item2-item3-item4-no
array.Join("-");

//item1-item2-item3-item4
array.Join("-", "x => x.length > 2");

Aggregate

Combines the entries using a custom function

var array = ["item1", "item2", "item3", "item4", "no"];

//no-item4-item3-item2-item1
array.Aggregate("(str, item) => item + '-' + item");

ToDictionary

Converts the array to a dictionary

var array = [{OtherId: 1, Value: "item1"}, {OtherId: 2, Value: "item2"}];

//{1: {OtherId: 1, Value: "item1"}, 2: {OtherId: 2, Value: "item2"}}
array.ToDictionary("x => x.OtherId");

//{1: "item1", 2: "item2"}
array.ToDictionary("x => x.OtherId", "x => x.Value");

Zip

Combines the entries of two arrays using a custom function

var array = [0, 1, 2, 3, 4];
var array2 = ["zero", "one", "two", "three"];

//["0 zero", "1 one", "2 two", "3 three"]
array.Zip(array2, "(x, y) => x + ' ' + y");

Reverse

Reverses the array

var array = ["item1", "item2", "item3", "item4", "no"];

//["no", "item4", "item3", "item2", "item1"]
array.Reverse();

Average

Computes the average of the elements

var array = [{val: 5}, {val: 3}, {val: 1}];

//3
array.Average("x => x.val");

//4
array.Average("x => x.val", "x => x.val > 1");


var array2 = [3, 4, 5];

//4
array2.Average();

Sum

Computes the sum of the elements

var array = [{val: 5}, {val: 3}, {val: 1}];

//9
array.Sum("x => x.val");

//8
array.Sum("x => x.val", "x => x.val > 1");


var array2 = [3, 4, 5];

//12
array2.Sum();

First

Returns the First item of the array and if a filter was set the first item that matches the filter - Throws an Exception if no item was found

var array = ["no", "item1", "item2", "item3", "item4", "no"];

//"no"
array.First();

//"item1"
array.First("i => i.match(/item/gi)");

//Exception
array.First("i => i == 'notgiven'");

FirstOrDefault

Returns the First item of the array and if a filter was set the first item that matches the filter - returns null if no suitable item was found

var array = ["no", "item1", "item2", "item3", "item4", "no"];

//"no"
array.FirstOrDefault();

//"item1"
array.FirstOrDefault("i => i.match(/item/gi)");

//null
array.First("i => i == 'notgiven'");

Min

Returns the smallest element in array

var array = [0, 8, 1, 5, -3];

//-3
array.Min();

var array = [{name: "test", age: 3}, {name: "test2", age: 18}];

//{name: "test", age: 3}
array.Min("x => x.age");

Last

Returns the Last item of the array and if a filter was set the last item that matches the filter - Throws an Exception if no item was found

var array = ["no", "item1", "item2", "item3", "item4", "no"];

//"no"
array.Last();

//"item4"
array.Last("i => i.match(/item/gi)");

//Exception
array.Last("i => i == 'notgiven'");

LastOrDefault

Returns the Last item of the array and if a filter was set the last item that matches the filter - returns null if no suitable item was found

var array = ["no", "item1", "item2", "item3", "item4", "no"];

//"no"
array.LastOrDefault();

//"item4"
array.LastOrDefault("i => i.match(/item/gi)");

//null
array.LastOrDefault("i => i == 'notgiven'");

Max

Returns the greates element in array

var array = [0, 8, 1, 5, -3];

//8
array.Max();

var array = [{name: "test", age: 3}, {name: "test2", age: 18}];

//{name: "test2", age: 18}
array.Max("x => x.age");

Select

Select the properties for a new array

var array = [{Id: 1, Value: "item1"}, {Id: 2, Value: "item2"}];
    
//["item1", "item2"]
array.Select("i => i.Value");

//[{Custom: 1, Name: "item1"}, {Custom: 2, Name: "item2"}];
array.Select("i => {Custom: i.Id, Name: i.Value}");

Take

Limits the Number of entries taken

var array = ["item1", "item2", "item3", "item4"];

//["item1", "item2"]
array.Take(2);

TakeWhile

Takes entries as long as a condition is true

var array = ["item1", "item2", "item3", "item2", "item4"];
var item2count = 0;

//["item1", "item2", "item3"]
array.TakeWhile(function(x){
    if(x == "item2"){
        item2count++;
    }

    return item2count < 2;
});

This is the basic usage. But if you want conditional executes for e.g. with counting this can get a little bit messy.

var array = ["item1", "item2", "item3", "item2", "item4"];

//["item1", "item2", "item3"]
array.TakeWhile(function(item, storage){
    return item != "item2" || storage.count < 1; //Condition
}, function(storage){
    storage.count = 0; //Init the Storage
}, function(item, storage){
    if(item == "item2"){
        storage.count++; //After executing the condition
    }
});

Skip

Skips entries

var array = ["item1", "item2", "item3", "item4"];

//["item3", "item4"]
array.Skip(2);

GroupBy

Group Array by Property

var array = [
    {name: "Max", age: 17},
    {name: "Emily", age: 54},
    {name: "max", age: 32},
    {name: "emily", age: 12}
];

//[
//	[{name: "Emily", age: 54},{name: "emily", age: 12}],
//	[{name: "Max", age: 17},{name: "max", age: 32}]
//]
array.GroupBy("i => i.name.toLowerCase()");

OrderBy & OrderByDescending

Order Array by Property or Value

var array = ["item3", "item1", "item2", "item4"];
    
//["item4", "item3", "item2", "item1"]
array.OrderByDescending("i => i");
    
//["item1", "item2", "item3", "item4"]
array.OrderBy("i => i");

Also supports complex Properties

var array = [
    {Name: "Max", Lastname: "Mustermann"},
    {Name: "John", Lastname: "Doe"},
    {Name: "Erika", Lastname: "Mustermann"}
];
    
//[{Name: "Max", Lastname: "Mustermann"},
//{Name: "Erika", Lastname: "Mustermann"},
//{Name: "John", Lastname: "Doe"}]
array.OrderByDescending("i => i.Lastname");

//[{Name: "John", Lastname: "Doe"}, 
//{Name: "Max", Lastname: "Mustermann"},
//{Name: "Erika", Lastname: "Mustermann"}]
array.OrderBy("i => i.Lastname");

ThenBy & ThenByDescending

Order Array by additional Properties in combination with OrderBy/OrderByDescending

var array = [
    {Name: "Max", Lastname: "Mustermann"},
    {Name: "John", Lastname: "Doe"},
    {Name: "Erika", Lastname: "Mustermann"}
];
    
//[{Name: "Erika", Lastname: "Mustermann"},
//{Name: "Max", Lastname: "Mustermann"},
//{Name: "John", Lastname: "Doe"}]
array.OrderByDescending("i => i.Lastname").ThenBy("i => i.Name");

Move

Moves an item from one index to another

var array = ["item1", "item2", "item3", "item4"];

//["item1", "item3", "item4", "item2"]
array.Move(1, 3);

Distinct

Makes all values unique using the specified selector

var array = ["item1", "item2", "item2", "item3", "item4"];

//["item1", "item2", "item3", "item4"]
array.Distinct("x => x");

If you want to select the last value in the order set a second parameter to true

var array = ["item1", "item2", "item2", "item3", "item4"];

//["item1", "item2", "item3", "item4"]
array.Distinct("x => x", true);

Author

Morris Janatzek (morrisjdev)