Inhomogeneous Field Values

This page discusses how FireSageJS tackles the homogeneous FieldValue types.

note

All interfaces use the same signature { symbol: unique symbol }.

Field Values

There are 2 field values in RTDB:

And they all sharing the same type: object, which means is it possible to assign any field value to any field value, and this open up to mistakes.

FireSageJS solves this by assigning unique symbol type:

Field Value	Interface	Note	Assignable
`serverTimestamp`	`ServerTimestamp`		Yes
`increment`	`Increment`	auto union with `number`	No

Increment are not assignable types and are not exported, it is a passive type that automatically union with number.

Interface	Note	Assignable
`Removable`	allow a node to be read as `undefiend` \| `null` and be removeable	Yes
`PossiblyReadAsNullable`	allow a node to be read as `undefiend` \| `null`	Yes
`PushAbleOnly`	be pushable only	Yes
`PushAble`	be pushable, set-able and updatable	Yes
`NumericKeyRecord<T>`	is Record<`${number}`, T> under the hodd	Yes

Special types have no real value, they serve as utilities, eg: transform into another type or allow you to perform certain action to a node.