Elysia.js

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Derive ​

Just like state and decorate, derive allows you to customize Context based on existing Context as Context.store.

This is useful when you to need to create a value based on an existing value reactively.

Example ​

typescript
app
    .state('version', 1)
    .decorate('getDate', () => Date.now())
    .derive(({ request: { headers }, store, getDate }) => {
        return {
            authorization: headers.get('Authorization')
        }
    })
    .get('/version', ({ authorization }) => authorization
)

app
    .state('version', 1)
    .decorate('getDate', () => Date.now())
    .derive(({ request: { headers }, store, getDate }) => {
        return {
            authorization: headers.get('Authorization')
        }
    })
    .get('/version', ({ authorization }) => authorization
)