The localForage is an open-source JavaScript library that refines the experience of saving data to web browser databases like localStorage, IndexedDB or WebSQL API.

It supports the majority of all types of browser databases.

It is absolutely asynchronous that simply uses browser databases and improves the universal offline experience of the web app.

In this tutorial, we’ll see how to save data to browsers in a much easier way with localforage setItem() method.

Localforage setItem() method

With localforage setItem(), developers are allowed to store multiple types of data not just strings.
It automatically manages and loads the best web browser driver(IndexedDB, WebSQL, and localStorage drivers).
It also supports to store blob and arbitrary type of data, so that we can store images, files, etc.
It also supports ES6 Promises.

Syntax

setItem(key, value, successCallback);

Types of supported JavaScript objects

Array
ArrayBuffer
Blob
Float32Array
Float64Array
Int8Array
Int16Array
Int32Array
Number
Object
Uint8Array
Uint8ClampedArray
Uint16Array
Uint32Array
String

Example

const user = {
  firstName: "Lionel",
  lastName: "Messi",
  profession: "Footballer ⚽ 🏃",
};

localforage
  .setItem("userDetails", user)
  .then((value) => {
    console.log(value.firstName + " " + value.lastName);
  })
  .catch((error) => {
    console.error(error);
  });

localforage
  .getItem("userDetails")
  .then(function (value) {
    // This code runs once the value has been loaded
    // from the offline store.
    console.log(value.firstName + " " + value.lastName + " is one of the most popular " + value.profession . " of all time.");
  })
  .catch(function (err) {
    // This code runs if there were any errors
    console.log(err);
  });

Output in console

👩‍🎤 Sunidhi Chauhan

Screenshot for localforage setItem() example

Multiple instances

The localforage also allows developers to create multiple instances using createInstance() method, pointing to different stores.

var asianCountries = localforage.createInstance({
  countries: ["India 🇮🇳", "Singapore 🇸🇬", "Israel 🇮🇱", "Japan 🇯🇵"],
});

var europeanCountries = localforage.createInstance({
  countries: ["Italy 🇮🇹", "France 🇫🇷", "Switzerland 🇨🇭", "Sweden 🇸🇪"],
});

// Setting the key on one of these doesn't affect the other.
asianCountries.setItem("asianLanguages", [
  "Hindi",
  "English",
  "Gujarati",
  "Japanese",
  "Hebrew",
]);

europeanCountries.setItem("europeanLanguages", [
  "Italian",
  "English",
  "Romansh",
  "Finnish",
]);