Interface Val<TValue>

A Val contains a writable value property and a set method.

interface Val<TValue> {
    $version: any;
    get: (() => TValue);
    set: ((value) => void);
    value: TValue;
    $valCompute(subscriber): ValDisposer;
    dispose(): void;
    reaction(subscriber, eager?): ValDisposer;
    ref(): ReadonlyVal<TValue>;
    ref(writable?): ReadonlyVal<TValue>;
    ref(writable): Val<TValue>;
    ref(writable?): Val<TValue> | ReadonlyVal<TValue>;
    subscribe(subscriber, eager?): ValDisposer;
    unsubscribe(subscriber?): void;
}

Type Parameters

  • TValue = any

Hierarchy (view full)

Properties

$version get set value

Methods

$valCompute dispose reaction ref subscribe unsubscribe

Properties

Readonly $version

$version: any

A version representation of the value. If two versions of a val is not equal(Object.is), it means the value has changed (event if the value is equal).

get

get: (() => TValue)

Get current value of the val.

Type declaration

set

set: ((value) => void)

Set new value

Type declaration

    • (value): void

    • Parameters

      Returns void

value

value: TValue

Current value of the val

Methods

$valCompute

  • $valCompute(subscriber): ValDisposer

  • Subscribe to value changes without immediate emission. The subscribers will be called before sync and async subscribers from [[reaction]] and [[subscribe]]. It is mainly used for chaining Vals.

    Parameters

    Returns ValDisposer

    a disposer function that cancels the subscription

dispose

reaction

  • reaction(subscriber, eager?): ValDisposer

  • Subscribe to value changes without immediate emission.

    Parameters

    • subscriber: ValSubscriber<TValue>
    • Optional eager: boolean

      by default subscribers will be notified on next tick. set true to notify subscribers of value changes synchronously.

    Returns ValDisposer

    a disposer function that cancels the subscription

ref

  • ref(): ReadonlyVal<TValue>

  • Create a new ReadonlyVal referencing the value of the current ReadonlyVal as source. (It is just like derive a val without transform. It is simpler hence more efficient.) All ref ReadonlyVals share the same value from the source ReadonlyVal.

    With this pattern you can pass a ref ReadonlyVal to downstream. The ref ReadonlyVals can be safely disposed without affecting the source ReadonlyVal and other ref ReadonlyVals.

    Returns ReadonlyVal<TValue>

  • ref(writable?): ReadonlyVal<TValue>

  • Create a new ReadonlyVal referencing the value of the current ReadonlyVal as source. (It is just like derive a val without transform. It is simpler hence more efficient.) All ref ReadonlyVals share the same value from the source ReadonlyVal.

    With this pattern you can pass a ref ReadonlyVal to downstream. The ref ReadonlyVals can be safely disposed without affecting the source ReadonlyVal and other ref ReadonlyVals.

    Parameters

    • Optional writable: false

    Returns ReadonlyVal<TValue>

  • ref(writable): Val<TValue>

  • Create a new Val referencing the value of the current Val as source. All ref Vals share the same value from the source Val. The act of setting a value on the ref Val is essentially setting the value on the source Val.

    With this pattern you can pass a ref Val as a writable Val to downstream. The ref Vals can be safely disposed without affecting the source Val and other ref Vals.

    Parameters

    • writable: true

    Returns Val<TValue>

  • ref(writable?): Val<TValue> | ReadonlyVal<TValue>

  • Parameters

    • Optional writable: boolean

      If true, creates a new Ref Val referencing the value of the current Val as source. If false, creates a new Ref ReadonlyVal referencing the value of the current Val as source.

    Returns Val<TValue> | ReadonlyVal<TValue>

subscribe

  • subscribe(subscriber, eager?): ValDisposer

  • Subscribe to value changes with immediate emission.

    Parameters

    • subscriber: ValSubscriber<TValue>
    • Optional eager: boolean

      by default subscribers will be notified on next tick. set true to notify subscribers of value changes synchronously.

    Returns ValDisposer

    a disposer function that cancels the subscription

unsubscribe

  • unsubscribe(subscriber?): void

  • Remove the given subscriber. Remove all if no subscriber provided.

    Parameters

    • Optional subscriber: ((...args) => any)
        • (...args): any

        • Parameters

          • Rest ...args: any[]

          Returns any

    Returns void

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