README

array-differences

Find the differences between two arrays and their positions.

Installation

npm install array-differences --save

yarn add array-differences

Usage

import arrayDifferences from 'array-differences'

const input = [0, 1, 1, 4, 1, 1]
const output = [111, 1, 112, 1, 4, 1]
const diff = arrayDifferences(input, output)

--> [['modified', 0, 111], ['inserted', 2, 112], ['deleted', 5]]

Using a custom comparison function:

const diff = arrayDifferences(
  [{ name: 'John' }, { name: 'Marie' }],
  [{ name: 'John' }, { name: 'Marie' }, { name: 'Chloe' }],
  (a, b) => a.name === b.name
)

--> [['inserted', 2, { name: 'Chloe' }]]

You can recontruct the second array by iterating over the differences on the first array or using the utility:

import { reconstructArray } from 'array-differences'

const reconstructed = reconstructArray(input, diff) // builds the output

// You can reconstruct in place:
reconstructArray(input, diff, true) // modifies input to recreate output from diff

Undefined values

The algorythm does not support arrays containing undefined values. Please replace your undefined values with a placeholder before applying it.

Performance on large arrays

Entry one is length n,

Entry two is length m,

Perfomance is n * n * m.

Therefore, it works best on smaller first arrays or if growing an array. Performance is best when differences indexes are close to one another in the array.

License

MIT

Usage no npm install needed!