simple-update-in
A lightweight updateIn
for immutable objects.
We love ImmutableJS. But sometimes, we want to start something from small. Thus, we created this package with zero dependencies.
Under the cover, we use Rest Operator to do most of the heavylifting.
Install
For latest stable, run npm install simple-update-in
.
For active development (master
branch), run npm install simple-update-in@master
.
How to use
We share similar signature as ImmutableJS.updateIn:
updateIn(target: Array|Map, path: (Number|String)[], updater?: (value: any) => any)
To make updateIn
efficient, especially, when paired with React. It will return a mixed deep/shallow clone of the target
. It only deep clone on objects that it modified along the path
, and shallow clone objects that it did not modify.
Example
Just like ImmutableJS, we want to make both Array
and Map
a first-class citizen. To work on a map, use a string
as key. For arrays, use a number
as key.
Map
import updateIn from 'simple-update-in';
const from = { one: 1, two: { number: 2 }, thirty: 3 };
const actual = updateIn(from, ['thirty'], three => three * 10);
expect(actual).toEqual({ one: 1, two: { number: 2 }, thirty: 30 });
expect(actual).not.toBe(from);
expect(actual.two).toBe(to.two);
expect(actual.thirty).toBe(30);
This is in fact an "upsert" operation.
Array in map
const from = { one: [1.1, 1.2, 1.3], two: [2] };
const actual = updateIn(from, ['one', 1], value => 'one point two');
expect(actual).toEqual({ one: [1.1, 'one point two', 1.3], two: [2] });
Remove a key
You can also use updateIn
to remove a key by passing a falsy value to the updater
argument.
const from = { one: 1, two: 2 };
const actual = updateIn(from, ['two']);
expect(actual).toEqual({ one: 1 });
expect(actual).not.toBe(from);
expect(actual).not.toHaveProperty('two');
Remove an item in array
const from = ['zero', 'one', 'two'];
const actual = updateIn(from, [1]);
expect(actual).toEqual(['zero', 'two']);
How about adding an item in an array?
Adding an item in an array is different than "upsert"-ing in a map. As we want to keep the learning curve very low, thus, we don't want to introduce syntax to do the insertion.
You can use the following code to insert an item with Rest Operator:
const from = { numbers: ['zero', 'one'] };
const actual = updateIn(from, ['numbers'], array => [...array, 'two']);
expect(actual).toEqual({ numbers: ['zero', 'one', 'two'] });
Contributions
Like us? Star us.
Want to make it better? File us an issue.
Don't like something you see? Submit a pull request.