Introduction

Ladda is an independent, lightweight caching solution for your JavaScript application. It is a library simple to get started with yet supports sophisticated cache management. In this section we will to explain how it can be useful for you and how to proceed if you want to give Ladda a shot.

How Does It Help Me?

Nowadays applications often are centered around the Create, Read, Update and Delete (CRUD) operations. You get a list of items from an API, want to update and delete an item or maybe create a new item.

Ladda caches your CRUD operations. When you get the list of items, it will cache the result. Every subsequent time you get the list of items, the cached result will be used. You don't perform the request.

In pseudo code, an ad-hoc caching solution often looks like the following:

var result;

if (/* check if result is cached */) {
  // get result from cache
  result = cache.getList();
} else {
  // get result from API
  result = apiService.getList();

  // store result in cache
  cache.put(/* store result and index */)
}

return result;

In contrast to this, Ladda shields away the cache layer for you and you end up with:

return apiService.getList();

The getList() request would look the same from the outside. You only reach out to your API layer to handle the request. At the place where you define the API layer, Ladda would be a thin decorator for your getList() functionality.

getList.operation = 'READ';
function getList() {
  // API request
}

That's only the READ operation in CRUD though. A simple ad-hoc caching solution (as above) doesn't support the CREATE, UPDATE or DELETE operations. Those are a bit more difficult to implement and that's where Ladda will help you.

Ladda does support those operations. When you update the list, by using a CREATE, UPDATE or DELETE operation, the requests are made to the API as usual. However, Ladda will also update your cache. Once you request the list of items again from the API, you will get the updated result from the cache without making a new API-request. For example, if you changed the name of a user, there's no need to refetch all users from your backend. Ladda ensures that you get up to date data if you would for example call "getAllUsers" again, without an API-request being made.

When to Use Ladda

Ladda is not meant to cover all possible use cases. To get the full power of Ladda you need to have well-defined entities. For example, you might have an entity User, which contains an id, name, email and contact details. Then you might have an entity ListUser, which only contains an id and a name. The important bit is that these concepts exist and that you refer to them as User and ListUser rather than "A user might have an id, name, email and contact details, but sometimes only id and name".

Of course, if you come up with creative ways of using Ladda, go ahead! You can quite easily use Ladda just as a simple cache for external calls, in which case you don't need a well-defined entity. But to leverge the more advanced parts, well-defined entities are necessary.

Next Steps

You should convince yourself by trying the Demos. Keep in mind that Ladda comes with more advantages than being a simple READ operation cache. It supports all the CRUD operations. Ladda keeps your cache in sync and minimizes the number of requests made to the backend. Data is only refetched if it has to be.

If you already want to get started, checkout the Getting Started section.