Package Exports

array-join

This package does not declare an exports field, so the exports above have been automatically detected and optimized by JSPM instead. If any package subpath is missing, it is recommended to post an issue to the original package (array-join) to support the "exports" field. If that is not possible, create a JSPM override to customize the exports field for this package.

Readme

array-join

Join arrays of objects by a common key or with a custom match function, similarly to how SQL JOIN and LEFT JOIN work.

Installation

$ npm install array-join

$ yarn add array-join

Usage

join(array1, array2, options)

leftJoin(array1, array2, options)

options = {
  key1,  // key property in the array1 objects to join objects on
  key2,  // key property in the array2 objects to join objects on
  key,  // common join key (when key1 is the same as key2)
  propMap1,  // function to rename properties of the array1 objects
  propMap2,  // function to rename properties of the array2 objects
  match  // custom match function to join objects in arrays
};

Examples

join objects on the common key property:

const join = require('array-join').join;

const result = join([
    { id: 1, name: 'apple' },
    { id: 2, name: 'banana' },
    { id: 3, name: 'orange' }
  ],
  [
    { id: 1, color: 'red' },
    { id: 2, color: 'yellow' },
    { id: 4, color: 'blue' }
  ],
  { key: 'id' });

console.log(result);

/*
[
  { id: 1, name: 'apple', color: 'red' },
  { id: 2, name: 'banana', color: 'yellow' }
]
*/

join objects on different key properties:

const result = join([
    { id: 1, name: 'apple' },
    { id: 2, name: 'banana' },
    { id: 3, name: 'orange' }
  ],
  [
    { num: 1, color: 'red' },
    { num: 2, color: 'yellow' },
    { num: 4, color: 'blue' }
  ],
  { key1: 'id', key2: 'num' });

console.log(result);

/*
[
  { id: 1, name: 'apple', color: 'red' },
  { id: 2, name: 'banana', color: 'yellow' }
]
*/

object properties can be renamed to avoid possible collisions:

const result = join([
    { id: 1, name: 'apple' },
    { id: 2, name: 'banana' },
    { id: 3, name: 'orange' }
  ],
  [
    { id: 2, name: 'Venus' },
    { id: 3, name: 'Mars' },
    { id: 4, name: 'Jupiter' }
  ],
  { key: 'id', propMap1: p => 'l_' + p, propMap2: p => 'r_' + p });

console.log(result);

/*
[
  { l_id: 2, r_id: 2, l_name: 'banana', r_name: 'Venus' },
  { l_id: 3, r_id: 2, l_name: 'orange', r_name: 'Mars' }
]
*/

join objects with a custom match function:

const result = join([
    { id: '100', name: 'one' },
    { id: '200', name: 'two' },
    { id: '300', name: 'three' }
  ],
  [
    { index: 1 },
    { index: 2 },
    { index: 3 }
  ],
  {
    match: (left, right) => Number(left.id) === 100 * right.index
  });

console.log(result);

/*
[
  { id: '100', name: 'one', index: 1 },
  { id: '200', name: 'two', index: 2 },
  { id: '300', name: 'three', index: 3 }
]
*/

left-join adds all items from the left array to the result (even if they don't match):

const leftJoin = require('array-join').leftJoin;

const result = leftJoin([
    { id: 1, name: 'apple' },
    { id: 2, name: 'banana' },
    { id: 3, name: 'orange' },
    { id: 4, name: 'apricot' }
  ],
  [
    { id: 1, color: 'red' },
    { id: 2, color: 'yellow' },
    { id: 5, color: 'blue' }
  ],
  { key: 'id' });

console.log(result);

/*
[
  { id: 1, name: 'apple', color: 'red' },
  { id: 2, name: 'banana', color: 'yellow' },
  { id: 3, name: 'orange' },
  { id: 4, name: 'apricot' }
]
*/