Iterama

Composable functional Iterable<T> helpers.

Install

npminstalliterama

concat

<T> (...iterables: Iterable<T>[]) => Iterable<T>

import{concat}from'iterama'constdata0=[1,2,3],data1=[4,5,6]constresult=[
...concat(data0,data1)]// [1, 2, 3, 4, 5, 6]

distinct

<T> (iterable: Iterable<T>) => Iterable<T>

import{distinct}from'iterama'constresult=[
...distinct([1,1,3,3,4,3])]// [1, 3, 4, 3]

filter

<T> (predicate: (arg: T) => boolean) => (iterable: Iterable<T>) => Iterable<T>

import{filter}from'iterama'constisEven=(x: number)=>x%2===0constresult=[
...filter(isEven)([1,2,3,4])]// [2, 4]

filterEx

<T> (predicate: (arg: T, index: number, it: Iterable<T>) => boolean) => (iterable: Iterable<T>) => Iterable<T>

import{filterEx}from'iterama'constskipEverySecond=(x: string,i: number)=>i%2!==0constresult=[
...filterEx(skipEverySecond)(['a','b','c','d'])]// ['a', 'c']

iterate

<T> (iterable: Iterable<T>) => IterableIterator<T>

import{iterate}from'iterama'constresult=[
...iterate([1,2,3,4,5])]// [1, 2, 3, 4, 5]

length

(maxLength: number) => <T> (iterable: Iterable<T>) => number

import{length}from'iterama'constl=length(Number.MAX_SAFE_INTEGER)constresult=l([1,2,3,4,5])// 5

map

<T, R> (xf: (arg: T) => R) => (iterable: Iterable<T>) => Iterable<R>

import{map}from'iterama'constmult2=(x: number)=>x*2constresult=[
...map(mult2)([1,2,3,4])]// [2, 4, 6, 8]

mapEx

<T, R> (xf: (arg: T, i: number, it: Iterable<T>) => R) => (iterable: Iterable<T>) => Iterable<R>

import{mapEx}from'iterama'constaddIndex=(x: number,i: number)=>x+iconstresult=[
...mapEx(addIndex)([1,2,3,4])]// [1, 3, 5, 7]

range

(length: number) => Iterable<number>

import{range}from'iterama'constresult=[
...range(4)]// [0, 1, 2, 3]

reduce

<T, R> (reducer: (a: R, b: T) => R) => (iterable: Iterable<T>) => Iterable<R>

import{reduce}from'iterama'// redux like reducerconstreducer=(state: number=0,b: number=0)=>a+bconstresult=[
...reduce(reducer)([1,2,3,4])]// [10]

reduceEx

<T, R> (reducer: (a: R, b: T, i: number, it: Iterable<T>) => R, initial: R) => (iterable: Iterable<T>) => Iterable<R>

import{reduceEx}from'iterama'// JavaScript like reducerconstreducer=(acc: number,val: number,i: number)=>acc+valconstresult=[
...reduceEx(reducer,0)([1,2,3,4])]// [10]

scan

<T, R> (reducer: (a: R, b: T) => R) => (iterable: Iterable<T>) => Iterable<R>

import{scan}from'iterama'// redux like reducerconstreducer=(state: number=0,b: number=0)=>a+bconstresult=[
...scan(reducer)([1,2,3,4])]// [1, 3, 6, 10]

scanEx

<T, R> (reducer: (a: R, b: T, i: number, it: Iterable<T>) => R) => (iterable: Iterable<T>) => Iterable<R>

import{scanEx}from'iterama'// JavaScript like reducerconstreducer=(acc: number,val: number,i: number)=>acc+valconstresult=[
...scanEx(reducer,0)([1,2,3,4])]// [1, 3, 6, 10]

skip

(n: number) => <T> (iterable: Iterable<T>) => Iterable<T>

import{skip}from'iterama'// skip first 2 itemsconstresult0=[
...skip(2)([1,2,3,4,5,6])]// [3, 4, 5, 6]// skip all until 2 items to the endconstresult1=[
...skip(-2)([1,2,3,4,5,6])]// [1, 2, 3, 4]

slice

(skip: number, take: number) => <T> (it: Iterable<T>): Iterable<T>

import{slice}from'iterama'// skip 1, take 2constr0=[
...slice(1,2)([1,2,3,4,5])]// [2, 3]// skip until 2 from end, take 1constr1=[
...slice(-2,1)([1,2,3,4,5])]// [4]// don't skip, take last 2constr2=[
...slice(0,-2)([1,2,3,4,5])]// [1, 2, 3]// skip 2, take the restconstr3=[
...slice(2)([1,2,3,4,5])]// [3, 4, 5]// skip until 2 from end, take the restconstr4=[
...slice(-2)([1,2,3,4,5])]// [4, 5]// don't skip, take allconstr5=[
...slice()([1,2,3,4,5])]// [1, 2, 3, 4, 5]

startWith

<T> (value: T) => (iterable: Iterable<T>)

import{startWith}from'iterama'constr=[
...startWith(0)([1,2,3])]// [0, 1, 2, 3]

take

(n: number) => <T> (iterable: Iterable<T>) => Iterable<T>

import{take}from'iterama'// take 2 first items, skip the restconstr0=[
...take(2)([1,2,3,4,5])]// [1, 2]// take 2 last items constr1=[
...take(-2)([1,2,3,4,5])]// [4, 5]

unique

<T> (iterable: Iterable<T>) => Iterable<T>

import{unique}from'iterama'constr=[
...unique([1,1,3,4,3])]// [1, 3, 4]

zip

<A, B> (it0: Iterable<A>, it1: Iterable<B>): Iterable<[A, B]><A, B, C> (it0: Iterable<A>, it1: Iterable<B>, it2: Iterable<C>): Iterable<[A, B, C]><A, B, C, D> (it0: Iterable<A>, it1: Iterable<B>, it2: Iterable<C>, it3: Iterable<C>): Iterable<[A, B, C, D]>

import{zip}from'iterama'constr=[
...zip([1,2,3,4,5,6],['a','b','c','d'])]// [ [1, 'a'], [2, 'b'], [3, 'c'], [4, 'd'] ]