Package Exports

object-diff
object-diff/index.js

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Readme

object diff

Get the minimal patch to extend literal object A with to transform it into literal object B

Consider an object retrieved from a server:

{
    name: 'Peter',
    age: 26,
    height: 187,
}

Now the user changes stuff using some frontend (e.g. a HTML form) and ends with:

{
    name: 'Peter',
    age: 27,
    height: 186,
}

When they hit save, you only want to send off the changed parts to the servers, to save bits (because you're indeed a programmer), but also to avoid any unnecessary "merge conflicts" at the server.

Imagine two users changing the same object; if they did not change the exact same keys of the object, the last user won't erase the first user's changes - in a lot of cases, that's the expected behavior.

Usage

const diff = require('object-diff')

const a = {
    speed: 4,
    power: 54,
    height: undefined,
    level: 1,
}

const b = {
    speed: 4, // unchanged
    power: 22, // changed
    level: undefined, // changed
    weight: 10, // added
}

diff(a, b)
/*
{
    power: 22,
    level: undefined,
    weight: 10,
}
*/

// using a custom equality function

const past = '2016-04-24T10:39:23.419Z'

diff.custom(
    (a, b) => {
        if (a instanceof Date && b instanceof Date) {
            return a.getTime() === b.getTime()
        }
        return a === b
    },
    {
        then: new Date(past),
    },
    {
        then: new Date(past),
    }
)
/*
{}
*/

ES5

For an ES5 friendlier version pin to 0.0.4. It has no known issues.