Pythonic NPM | npm.io

Pythonic

Python like utility functions for JavaScript: range, enumerate, items, zip and zipLongest.

These functions return an Iterator instance similar to Python Iterators. This Iterator implementation is lazy evaluated, offers map, filter, reduce, some, every and Symbol.asyncIterator interfaces.

Install

npm install pythonic --save

Functions

range

import {range} from 'pythonic';

range(3).map(x => console.log(x + 1));
// 1
// 2
// 3

for (const i of range(10, 25, 5))
    console.log(i);
// 10
// 15
// 20

console.log(range(5).reduce((accumulator, current) => accumulator + current));
// 10

enumerate

import {enumerate} from 'pythonic';

const arr = ['a', 'b'];
for (const [index, value] of enumerate(arr))
    console.log(`index: ${index}, value: ${value}`);
// index: 0, value: a
// index: 1, value: b

zip | zipLongest

import {zip, zipLongest} from 'pythonic';

const arr1 = ['a', 'b'];
const arr2 = ['c', 'd', 'e'];
for (const [first, second] of zip(arr1, arr2))
    console.log(`first: ${first}, second: ${second}`);
// first: a, second: c
// first: b, second: d

for (const [first, second] of zipLongest(arr1, arr2))
    console.log(`first: ${first}, second: ${second}`);
// first: a, second: c
// first: b, second: d
// first: undefined, second: e

// unzip
const [arrayFirst, arraySecond] = [...zip(...zip(arr1, arr2))];

items

import {items} from 'pythonic';

const obj = {a: 'aa', b: 'bb'};
for (const [key, value] of items(obj))
    console.log(`key: ${key}, value: ${value}`);
// key: a, value: aa
// key: b, value: bb

const map = new Map([[1, 'one'], [2, 'two']]);
for (const [key, value] of items(map))
    console.log(`key: ${key}, value: ${value}`);
// key: 1, value: one
// key: 2, value: two

Iterator

import {Iterator, range} from 'pythonic';

const randomIntegers = (size, start, stop) => new Iterator(function * () {
    for (const _ of range(size))
        yield Math.floor(Math.random() * (stop - start) + start);
});

const randomNumbers = randomIntegers(3, 10, 1000);

for (const randomNumber of randomNumbers)
    console.log(randomNumber);
// 685
// 214
// 202

console.log(randomNumbers.some(value => value > 10));
// true
console.log(randomNumbers.every(value => value < 1000));
// true