kirill-d-lappo/jslinq

jsSequence

Description

Yet another Enumerable adaptation on JS. Created for arrays only and bases on js iterators.

Very early and unfinished; do I have much time to complete it?...

NOTE: All equality operations are done with === operator, SameValue equality is not used.

Examples

require("jssequence");

let users = [
    {id:1, name:"Rick",  type:"grandpa", age:55, isActive:true},
    {id:2, name:"Morty", type:"boy", age:15, isActive:true},
    {id:2, name:"Jerry", type:undefined, age:28, isActive:false},
];

// Filtering and reflection
let activeUserIds = array
    // accessing to linq-like functions
    .seq()
    // It doesn't create a new array at this point
    // It just keeps info about sorting
    .where(u => u.isActive)
    // Just keeping info about selection, no new array here
    .select(u => u.id)
    // New array is created here, [1, 2]
    .toArray();

// Lets find an age of the first user which has 5 letters in his name
// Yeah, I'm a pervert
let fiveLetterUserAge = users.seq()
    .first(u => u.name.length === 5)
    .age;

// Combine user names, who is old enough ( >= 18)
let adultSwimUsers = users.seq()
    .where(u => u.age >= 18)
    .aggregate(
        (result, nextUser) => result + nextUser.name,
        "");

// Any granda here
let hasAnyGrandpaCharacter = users.seq()
    .where(u => u.type === "grandpa")
    .any()

// Or the expression could be shorter
hasAnyGrandpaCharacter = users.seq()
    .any(u => u.type === "grandpa")

Functions

Function	Description	Returns
.seq()	Special function, which returns sequence object. Entrypoint for ll other functions, which are described here.	Sequence Object
.select(function)	Similar to array.map function, reflects sequence nto another sequence using function	Sequence Object
.where(function)	Similar to filter functions, it filters items in a equence using function	Sequence Object
.skip(number)	Skips first number items in a sequence.	Sequence Object
.skip(function)	Skips first items in a sequence untill function returns true	Sequence Object
.skip(object)	Skips first items in a sequence untill items are not qual to object	Sequence Object
.take(number)	Takes first number items in a sequence	Sequence Object
.take(function)	Takes first items in a sequence untill function returns false	Sequence Object
.take(object)	Skips first items in a sequence untill items are not qual to object	Sequence Object
.takeUnit(unitIndex, unitSize)	Takes sub-sequence. Original sequence s splited by unitSize groups of items and unitIndexth group is eturned	Sequence Object
.concat(array)	Continues original sequence with array	Sequence Object
.distinct(array)	Returns sequence with unique items	Sequence Object
.first()	Returns first item from a sequence	Item
.first(function)	Returns first item from sequence, when function returns true	Item
.last()	Returns last item from sequence	Item
.last(function)	Returns last item from sequence, when function returns true	Item
.single(function)	Returns the only item from sequence, which makes function return true	Item
.all(function)	Returns true when function returns true for all tems in a sequence, false otherwise.	boolean
.any()	Returns true when sequence has at least one element, false therwise.	boolean
.any(function)	Returns true when function returns true for at east one item in a sequence, false otherwise.	boolean
.aggregate(function, object)	Similar to popular reduce function. Returns aggregated value, which is constructed with sequence items, function(currentResult, nextItem) and initial value object.	Object
.count()	Returns amount of elements in a sequence.	number
.count(function)	Returns amount of elements in a sequence for which function(item) returns true.	number
.contains(object)	Returns true when sequence contains object, false otherwise.	boolean
.elementAt(index)	Returns indexth object in a sequence.	Object
.toKeyValue(keyFunction, valueFunction)	Converts a sequence in to a ey-value object using keyFunction(item) and valueFunction(item).	bject
.toArray()	Converts a sequence into an array.	Array
.toArray(function)	Converts a sequence into an array using a value unction function(item).	Array