LoopBack 4 is a completely new framework, also known as LoopBack-Next.
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What’s the vision behind LoopBack 4?

  • Make it even easier to build apps that require complex integrations
  • Enabling an ecosystem of extensions
  • Small, fast, flexible, powerful core
  • Suitable for small and large teams
  • Minimally opinionated, enforce your team’s opinions instead

See Crafting LoopBack 4 for more details.

What’s the timeline for LoopBack 4?

See Upcoming releases.

Where are the tutorials?

See Examples and tutorials.

What features are planned ?

  • 100% promise-based APIs and async and await as first-class keywords.
  • Being able to choose to use JavaScript or TypeScript.
  • Better extensibility, ability to override any aspect of the framework (for example, no more built-in User - model pain, easily replace parts of ACL with your own).
  • Define APIs / remote methods with OpenAPI (Swagger).
  • Organize business and other logic into controllers with their own opinionated API or generate an PersistedModel style API.
  • Better routing performance
  • React SDK
  • Create GraphQL based APIs
  • GraphQL => juggler integration
  • Advanced declarative caching support
  • New DSL for defining APIs / Models
  • Completely new tooling w/ Visual Studio Code integration
  • More at Feature proposals

Add your feature requests at loopback-next/issues/new.

Why TypeScript?

Although developers can still write application logic in either JavaScript or TypeScript, LoopBack 4’s core is written in TypeScript, for the following reasons:

  • Improved developer productivity and scalability. Our customers need a framework that scales to dozens and even hundreds of developers. This scalability is the reason TypeScript exists and is gaining traction.
  • Improved extensibility and flexibility. LoopBack 4’s core is simpler than LoopBack 3.x with well-defined extension points. A lot of responsibility will be shifted to extensions (components), which can be JavaScript or TypeScript.
  • Unified tooling. TypeScript developers all use the same IDE: Visual Studio Code. The LoopBack ecosystem could someday be filled with useful best practices around that IDE and even great developer plugins. Right now that effort is split between various editors and basically non-existent.
  • Future-proofing. Ability to leverage the latest and future JavaScript constructs.

TypeScript’s support for static analysis makes more robust tooling possible and is the foundation for its scalability. The ability to easily refactor code without the common human-introduced errors. Dev and Compile time checking. For example, most people don’t have the same expertise and time we do to setup complex linting solutions (for example, a linting config that works across many projects).

For more details, see the lengthy discussion in #6.

Does JavaScript still work?

LoopBack 4 itself is written in TypeScript (that compiles to JavaScript), but it supports applications written in both TypeScript and JavaScript. The documentation assumes you have a basic understanding of the JavaScript language; and when it says “JavaScript” it is understood to mean ECMAScript version 6 (ES6).

Some of the examples use ES6 syntax. We encourage you to get familiar with ES6 constructs such as arrow functions, classes, template literals, let, and const statements.

LoopBack 3 vs LoopBack 4

See Differences between LoopBack v3 and v4.