update-immutable

Description

This is a mostly-compatible re-implementation of react's update function.

Usage (ES6)

import update from 'update-immutable';

let orig = { a: 1 };
let next = update(orig, { b: { $set: 2 } });

## next: { a: 1, b: 2 }
## orig: { a: 1 }

Features

The following new features/bugfixes have been implemented:

• Simple recursive implementation without dependencies

  The original version depends on react.

• Implements $unset

  The react team refuses to merge this functionality for some pretty dubious reasons. $unset is important for several use-cases.

• $unshift doesn't reverse

  The react version of $unshift unshifts each element in a loop, thereby reversing the provided list. This version fixes that bug and makes it work like perl's unshift.

• Supports auto-vivification

  Auto-vivification allows you to modify a nested data structure even if the nesting data-structures don't yet exist. They will be created so as to satisfy the update. This simplifies many use-cases, for example you don't need to maintain an initial-state skeleton.

Incompatibilities

This module is mostly compatible with the react version except for the following notes:

• Doesn't implement $apply

  This module is primarily intended for transferring incremental updates between browsers and server-side web apps. For this use case, $apply is not possible since functions cannot be serialised. If there is interest we may eventually implement $apply (pull requests welcome).

• $unset behaviour

  As described above, when passing multiple items in a single $unset update, the order of the items is preserved, unlike react which reverses the list.

Server-side

There is a companion perl module Update::Immutable that implements functionality identical to this module. This lets you process updates both server-side and on the client (provided your server is implemented in perl that is).

Copyright

(C) 2016 Doug Hoyte

2-clause BSD license