halfpipe

Halfpipe is a functional programming library containing a pipe function, composable and pipe-able functions, and monadic constructs.

Install Instructions:

npm install @tdameritrade/halfpipe

Usage:

Functions are split into "namespaces" that operate on specific types of entities. Currently supported namespaces include:

• Arrays
• Eithers
• Maps
• Maybes
• Objects
• Promises
• Sets
• Validations

To use, import the pipe function as well as the desired namespaces:

import { pipe, Objects } from '@tdameritrade/halfpipe';

const myObj = {
  x: 2,
  y: 4
};

const hasZ = pipe(
  myObj,
  Objects.has('z')
);

// hasZ === false

All functions are immutable:

import { pipe, Arrays } from '@tdameritrade/halfpipe';

const myArr = [1, 2, 3];

const reversedArr = pipe(
  myArr,
  Arrays.reverse()
);

// reversedArr === [ 3, 2, 1 ]
// myArr === [ 1, 2, 3 ]

Functions can easily be composed:

import { pipe, Arrays, Objects } from '@tdameritrade/halfpipe';

const myArr = [{ x: 2 }, { x: 3, y: 4 }, { y: 4 }];

const allHaveX = pipe(
  myArr,
  Arrays.every(Objects.has('x'))
);

// allHaveX === false

All functions that can return a potentially null/undefined value will return a Maybe instead:

import { pipe, Arrays, Objects, Maybes } from '@tdameritrade/halfpipe';

const myArr = [{ x: 1 }, { x: 4, y: 3 }, { x: 1, y: 2 }];

const firstXWithY = pipe(
  myArr,
  Arrays.find(Objects.has('y')),
  Maybes.flatMap(Objects.get('x')),
  Maybes.orNull()
);

// firstXWithY === 4