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ScalarSignalSource
Represents a source used to get and set the value of a ScalarSignal.
Typically, changing the value that a signal contains requires a total reassignment:
TouchGestures.onTap().subscribe((gesture) => {
someSignal = Reactive.val(1);
});
In the example above, someSignal is bound to a completely new signal which itself contains the desired value.
The ScalarSignalSource API provides the ability to change the value of the original signal without reassignment, with behavior similar to that of non-reactive programming models.
The Scripting Writeable Signal Source capability must be enabled within the project's Properties to use this API.
Example
//============================================================================
// Creates a new ScalarSignalSource object and change's the signal value
// on a screen tap event.
//
// Required project capabilities:
// - TouchGestures (auto added on module import)
// - Scripting Writeable Signal Source
//
//============================================================================
// Load in the required modules
const Reactive = require('Reactive');
const TouchGestures = require('TouchGestures');
const Diagnostics = require('Diagnostics');
(async function () { // Enables async/await in JS [part 1]
// Create a scalar signal source
var scalarSource = Reactive.scalarSignalSource("ScalarSource");
// Get the scalar signal from the source
const scalarSignal = scalarSource.signal;
// Set an initial value for the scalar signal
scalarSource.set(1);
// Add the signal to the Watch view
Diagnostics.watch("Scalar value: ", scalarSignal);
// Create a variable to keep track of the tap count
var count = 0;
// Update the scalar value each time a tap event is fired
TouchGestures.onTap().subscribe(() => {
// Increment 'count' value
count += 1;
// Set the value of the scalar signal to the value of 'count'
scalarSource.set(count);
});
})(); // Enables async/await in JS [part 2]Properties
| Property | Description |
|---|---|
signal | (get) signal: ScalarSignal The signal being monitored by the ScalarSignalSource object.Accessing the signal's value before one has been assigned via set() will return an empty string. |
Methods
| Method | Description |
|---|---|
dispose | dispose(): void Disposes of the native resources associated with the ScalarSignalSource object.The ScalarSignalSource object will still exist as a JavaScript object but will not receive updates through future calls to set(). Do not call dispose() until you're certain that the signal is no longer required.When calling ReactiveModule.scalarSignalSource, avoid reusing the sourceId of an object that you've called dispose() on. |
set | set(value: ScalarSignal | number): void Sets the value of the signal monitored by the ScalarSignalSource object to value.The updated signal value will be propagated throughout all signals related to the ScalarSignalSource.If set() is called before signal, signal will return the value assigned by set() when called, rather than the default empty string.* value - the value to assign to the signal, as a number or ScalarSignal. |