# varasto

[![Package Version](https://img.shields.io/hexpm/v/varasto)](https://hex.pm/packages/varasto)
[![Hex Docs](https://img.shields.io/badge/hex-docs-ffaff3)](https://hexdocs.pm/varasto/)

Typed access to the [Web Storage API](https://developer.mozilla.org/en-US/docs/Web/API/Web_Storage_API), i.e. LocalStorage and SessionStorage.

This package is only for the JavaScript target. It depends on [plinth](https://hexdocs.pm/plinth/index.html), which implements the lower level (string only) Web Storage API access. Thus, if you only intend to read and write string values, you may use plinth directly.

## Usage

Varasto uses JSON as the storage format. To use it, you will need to construct a `TypedStorage` value that encapsulates a reader and a writer to convert the value to and from `gleam/json.Json`.

An example where the data type is a list of integers:

```gleam
import gleam/dynamic
import gleam/json
import plinth/javascript/storage
import varasto

// Reader that decodes a Dynamic to a list of integers
fn int_list_reader() {
  dynamic.list(dynamic.int)
}

// A writer that converts a list of integers to a Json value
fn int_list_writer() {
  fn(val: List(Int)) { json.array(val, json.int) }
}

// First use plinth to get the low level storage
let assert Ok(local) = storage.local()

// Construct TypedStorage with the reader and writer
let s = varasto.new(local, int_list_reader(), int_list_writer())

// Set a value
varasto.set(s, "Foo", [1, 2, 3])

// Returns Ok([1, 2, 3])
varasto.get(s, "Foo")
```

## Installation

This package can be added to your Gleam project:

```sh
gleam add varasto
```

and its documentation can be found at <https://hexdocs.pm/varasto>.