Removable

This page discusses how to use Removable.

info

1. Removable unions nodes read type with null and undefined.
2. Removable allows nodes to be removed.

Type Checks

import {
    MetaTypeCreator,
    ServerTimestamp,
    NumericKeyRecord,
    Removable,
    createRef,
    getDatabase,
    remove,
    get,
} from 'firesagejs'

export type Example = MetaTypeCreator<{
    a: number | Removable
    b: number
}>
const exampleRef = createRef<Example>(getDatabase())

remove(exampleRef('a')) // ok

remove(exampleRef('b')) // not ok, because b is not removable

get(exampleRef()).then(dataSnapshot => {
    // type of data is { a: number | null | undefined; b: number} | null
    // Removable union node read type with null and undefined
    const data = dataSnapshot.val()
})

// you can union `Removable` to any node
export type Example2 = MetaTypeCreator<
    | {
            b:
                | {
                        c: boolean | Removable
                        d:
                            | {
                                    e: ServerTimestamp | Removable
                              }
                            | Removable
                  }
                | Removable
            f: Record<string, 'a' | 'b' | 'c' | Removable> | Removable
            i: NumericKeyRecord<boolean | Removable> | Removable
      }
    | Removable
>

how to use Removable

Understanding Error Messages

you can only remove Removanble node