@extend-chrome/storage

---

Manage Chrome Extension storage easily with @extend-chrome/storage.

This is a wrapper for the Chrome Extension Storage API that adds
great TypeScript support using virtual storage buckets with a modern Promise-based API.

Table of Contents

- Getting Started
- Usage

- Features
- API
- interface Bucket
- bucket.get()
- bucket.getKeys()
- bucket.set()
- bucket.remove()
- bucket.clear()
- bucket.changeStream
- bucket.valueStream
- function getBucket()

Getting started

You will need to use a bundler like
Rollup, Parcel, or Webpack to
include this library in your Chrome extension.

See rollup-plugin-chrome-extension for
an easy way to use Rollup to build your Chrome extension!

Installation

``sh
npm i @extend-chrome/storage
`

Usage

Add the storage permission to your manifest.json file.

`jsonc
// manifest.json
{
"permissions": ["storage"]
}
`

Take your Chrome extension to another level! 🚀

`javascript
import { storage } from '@extend-chrome/storage'

// Set storage using an object
storage.set({ friends: ['Jack'] })

// Set storage using a function
storage.set(({ friends }) => {
// friends is ['Jack']
return { friends: [...friends, 'Amy'] }
})

// Get storage value using a key
storage.get('friends').then(({ friends }) => {
// friends is ['Jack', 'Amy']
})

// Get storage values using an object
storage
.get({ friends: [], enemies: [] })
.then(({ friends, enemies }) => {
// friends is ['Jack', 'Amy']
// enemies is the [] from the getter object
})
`

Features

Virtual typed storage buckets

This library allows you to create a storage area and define the
type of data that area will manage.

`typescript
import { getBucket } from '@extend-chrome/storage'

interface Store {
a: string
b: number
}

const store = getBucket('store')

store.set({ a: 'abc', b })
store.set(({ b = 0 }) => ({ b: b + 500 }))

store.set({ c: true }) // ts error
store.set(({ a }) => ({ d: 'invalid' })) // ts error
`

Promises and functional setters

The Chrome Storage API is asynchronous. This means synchronous
calls to get and set will not reflect pending changes. This
makes calls to set that depend on values held in storage
difficult.

While the Chrome Storage API is async, it uses callbacks. This
brings a whole world of difficulty into the developer experience
that have been solved with Promises.

@extend-chrome/storage solves both of these problems. Every method
returns a Promise and both get and set can take a function
that provides current storage values, similar to React's
this.setState.

Composed set operations

The set method can be called with a function (setter) as well
as the normal types (a string, array of strings, or an object).

This setter will receive the entire contents of that storage area
as an argument. It must return an object which will be passed to
the native storage area set method.

Synchronous calls to set will be composed into one call to the
native set. The setters will be applied in order, but each call
will resolve with the final value passed to the storage area.

`javascript
bucket.set({ a: 123 })
bucket.set({ b: 456 })
bucket
.set(({ a, b }) => {
// a === 123
// b === 456
return { c: 789 }
})
.then(({ a, b, c }) => {
// New values in bucket
// a === 123
// b === 456
// c === 789
})
`

An individual call to set will reject if the setter function
throws an error or returns an invalid type, but will not affect
other set operations.

API

interface Bucket

A synthetic storage area. It has the same methods as the native
Chrome API StorageArea, but get and set can take a function as an
argument. A Bucket can use
either local or sync storage.

Multiple synchronous calls to set are composed into one call to
the native Chrome API
StorageArea.set.

Default storage areas are included, so you can just import
storage if you're don't care about types and only need one
storage area.

`javascript
import { storage } from '@extend-chrome/storage'

storage.local.set({ a: 'abc' })
storage.sync.set({ b: 123 })
`

Create a bucket or two using getBucket:

`javascript
import { getBucket } from '@extend-chrome/storage'

// Buckets are isomorphic, so export and
// use them throughout your extension
export const bucket1 = getBucket('bucket1')
export const bucket2 = getBucket('bucket2')
`

Each bucket is separate, so values don't overlap.

`javascript
bucket1.set({ a: 123 })
bucket2.set({ a: 'abc' })

bucket1.get() // { a: 123 }
bucket2.get() // { a: 'abc' }
`

Buckets really shine if you're using TypeScript, because you can
define the types your bucket will contain.
Click here for more details.

async function bucket.get

Takes an optional getter. Resolves to an object with the
requested storage area values.

`typescript
bucket.get('a') // resolves to object as key/value pair
bucket.get({ a: 123 }) // same, but 123 is default value
bucket.get(({ a }) => a) // resolves to value of "a"
`

async function bucket.getKeys

Takes an optional getter. Resolves to an array of strings that represents the keys of the values in the storage area bucket.

`typescript
function getKeys() => Promise
`

`typescript
bucket.set({ a: 123 })
bucket.getKeys() // Resolves to ['a']
`

async function bucket.set

Set a value or values in storage. Takes a setter object or
function. Resolves to the new bucket values.

`typescript
bucket.set({ a: 123 })
bucket
.set(({ a }) => ({ b: true }))
.then(({ a, b }) => {
// Values were set
// a === 123
// b === true
})
`

async function bucket.remove

Remove a value or values from storage. Resolves when the
operation is complete.

`typescript
bucket.remove('a')
bucket.remove(['a', 'b'])
`

async function bucket.clear

Empties only this bucket. Resolves when the operation is
complete. Other buckets are untouched.

`typescript
bucket.clear()
`

async function bucket.changeStream

An RxJs Observable that emits a
StorageChange
object when the Chrome Storage API onChanged event fires.

`typescript
bucket.changeStream
.pipe(filter(({ a }) => !!a))
.subscribe(({ a }) => {
console.log('old value', a.oldValue)
console.log('new value', a.newValue)
})
`

async function bucket.valueStream

An Observable that emits all the values in storage immediately,
and when onChanged fires.

`typescript
bucket.valueStream.subscribe((values) => {
console.log('Everything in this bucket', values)
})
`

function getBucket

Create a bucket (a synthetic storage area). Takes
a string bucketName and an optional string areaName. Returns
a Bucket synthetic storage area. Export this
bucket and use it throughout your Chrome extension. It will work
everywhere, including privileged pages and content scripts.

getBucket is a TypeScript Generic. Pass it an interface to
define the types to expect in your storage area.

`typescript
import { getBucket } from '@extend-chrome/storage'

// JavaScript
export const localBucket = getBucket('bucket1')
export const syncBucket = getBucket('bucket2', 'sync')

// TypeScript
export const localBucket = getBucket<{ a: string }>('bucket1')
export const syncBucket = getBucket<{ b: number }>(
'bucket2',
'sync',
)
``