Save Data To Offline Storage With Localforage

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: "Sunidhi",
  lastName: "Chauhan",
  profession: "Singer 🎤",
};

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

Output in console

👩‍🎤 Sunidhi Chauhan

Screenshot for localforage setItem() example
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",
]);

Hope you like this

Happy 😄 coding

With ❤️ from India 🇮🇳

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A web geek, an industry experienced web developer & tutor/instructor residing in India 🇮🇳

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