Remapping

As the name suggest, this allow us to remap existing state, decorate, model, derive to anything we like to prevent name collision, or just wanting to rename a property.

By providing a function as a first parameters, the callback will accept current value, allowing us to remap the value to anything we like.

new Elysia()
    .state({
        a: "a",
        b: "b"
    })
    // Exclude b state
    .state(({ b, ...rest }) => rest)

new Elysia()
    .state({
        a: "a",
        b: "b"
    })
    // Exclude b state
    .state(({ b, ...rest }) => rest)

This is useful when you have to deal with a plugin that has some duplicate name, allowing you to remap the name of the plugin:

new Elysia()
    .use(
        plugin
            .decorate(({ logger, ...rest }) => ({
                pluginLogger: logger,
                ...rest
            }))
    )

new Elysia()
    .use(
        plugin
            .decorate(({ logger, ...rest }) => ({
                pluginLogger: logger,
                ...rest
            }))
    )

Remap function can be use with state, decorate, model, derive to helps you define a correct property name and preventing name collision.

Affix

To provide a smoother experience, some plugins might have a lot of property value which can be overwhelming to remap one-by-one.

The Affix function, which consists of a prefix and suffix, allows us to effortlessly remap all properties of an instance, preventing the name collision of the plugin.

const setup = new Elysia({ name: 'setup' })
    .decorate({
        argon: 'a',
        boron: 'b',
        carbon: 'c'
    })

const app = new Elysia()
    .use(
        setup
            .prefix('decorator', 'setup')
    )
    .get('/', ({ setupCarbon }) => setupCarbon)

const setup = new Elysia({ name: 'setup' })
    .decorate({
        argon: 'a',
        boron: 'b',
        carbon: 'c'
    })

const app = new Elysia()
    .use(
        setup
            .prefix('decorator', 'setup')
    )
    .get('/', ({ setupCarbon }) => setupCarbon)

By default, affix will handle both runtime, type-level code automatically, remapping the property to camelCase as naming convention.

In some condition, you can also remap all property of the plugin:

const app = new Elysia()
    .use(
        setup
            .prefix('all', 'setup')
    )
    .get('/', ({ setupCarbon }) => setupCarbon)

const app = new Elysia()
    .use(
        setup
            .prefix('all', 'setup')
    )
    .get('/', ({ setupCarbon }) => setupCarbon)