feat(InputBinding): subscribe callback now supports event priority

NEWS.md

@@ -1,6 +1,14 @@
 # shiny (development version)
 
-## New features and improvements
+## New features
+
+* `textInput()`, `textAreaInput()`, `numericInput()` and `passwordInput()` all gain an `updateOn` option. `updateOn = "change"` is the default and previous behavior, where the input value updates immediately whenever the value changes. With `updateOn = "blur"`, the input value will update only when the text input loses focus or when the user presses Enter (or Cmd/Ctrl + Enter for `textAreaInput()`). (#4183)
+
+* The `callback` argument of Shiny.js' `InputBinding.subscribe()` method gains support for a value of `"event"`. This makes it possible for an input binding to use event priority when updating the value (i.e., send immediately and always resend, even if the value hasn't changed).
+
+## Improvements
+
+* When auto-reload is enabled, Shiny now reloads the entire app when support files, like Shiny modules, additional script files, or web assets, change. To enable auto-reload, call `devmode(TRUE)` to enable Shiny's developer mode, or set `options(shiny.autoreload = TRUE)` to specifically enable auto-reload. You can choose which files are watched for changes with the `shiny.autoreload.pattern` option. (#4184)
 
 * When busy indicators are enabled (i.e., `useBusyIndicators()`), Shiny now:
     * Shows a spinner on recalculating htmlwidgets that have previously rendered an error (including `req()` and `validate()`). (#4172)
@@ -11,10 +19,6 @@
 
 * Shiny's Typescript assets are now compiled to ES2021 instead of ES5. (#4066)
 
-* `textInput()`, `textAreaInput()`, `numericInput()` and `passwordInput()` all gain an `updateOn` option. `updateOn = "change"` is the default and previous behavior, where the input value updates immediately whenever the value changes. With `updateOn = "blur"`, the input value will update only when the text input loses focus or when the user presses Enter (or Cmd/Ctrl + Enter for `textAreaInput()`). (#4183)
-
-* When auto-reload is enabled, Shiny now reloads the entire app when support files, like Shiny modules, additional script files, or web assets, change. To enable auto-reload, call `devmode(TRUE)` to enable Shiny's developer mode, or set `options(shiny.autoreload = TRUE)` to specifically enable auto-reload. You can choose which files are watched for changes with the `shiny.autoreload.pattern` option. (#4184)
-
 ## Bug fixes
 
 * Fixed a bug with modals where calling `removeModal()` too quickly after `showModal()` would fail to remove the modal if the remove modal message was received while the modal was in the process of being revealed. (#4173)

srcts/src/bindings/input/inputBinding.ts

@@ -1,3 +1,4 @@
+import type { EventPriority } from "../../inputPolicies/inputPolicy";
 import type { RatePolicyModes } from "../../inputPolicies/inputRateDecorator";
 import type { BindScope } from "../../shiny/bind";
 
@@ -26,10 +27,16 @@ class InputBinding {
     el; // unused var
   }
 
-  // The callback method takes one argument, whose value is boolean. If true,
-  // allow deferred (debounce or throttle) sending depending on the value of
-  // getRatePolicy. If false, send value immediately. Default behavior is `false`
-  subscribe(el: HTMLElement, callback: (value: boolean) => void): void {
+  // Historically, the callback value could only be boolean. In this case:
+  //   * false: send value immediately (i.e., priority = "immediate")
+  //   * true: send value later (i.e., priority = "deferred")
+  //     * The input rate policy is also consulted on whether to debounce or throttle
+  // In recent versions, the value can also be "event", meaning that the
+  // value should be sent regardless of whether it has changed.
+  subscribe(
+    el: HTMLElement,
+    callback: (value: EventPriority | boolean) => void
+  ): void {
     // empty
     el; // unused var
     callback; // unused var

srcts/src/shiny/bind.ts

@@ -8,6 +8,7 @@ import type {
   InputRateDecorator,
   InputValidateDecorator,
 } from "../inputPolicies";
+import type { InputPolicyOpts } from "../inputPolicies/inputPolicy";
 import { shinyAppBindOutput, shinyAppUnbindOutput } from "./initedMethods";
 import { sendImageSizeFns } from "./sendImageSize";
 
@@ -27,7 +28,7 @@ function valueChangeCallback(
   inputs: InputValidateDecorator,
   binding: InputBinding,
   el: HTMLElement,
-  allowDeferred: boolean
+  priority: InputPolicyOpts["priority"]
 ) {
   let id = binding.getId(el);
 
@@ -37,17 +38,7 @@ function valueChangeCallback(
 
     if (type) id = id + ":" + type;
 
-    const opts: {
-      priority: "deferred" | "immediate";
-      binding: typeof binding;
-      el: typeof el;
-    } = {
-      priority: allowDeferred ? "deferred" : "immediate",
-      binding: binding,
-      el: el,
-    };
-
-    inputs.setInput(id, value, opts);
+    inputs.setInput(id, value, { priority, binding, el });
   }
 }
 
@@ -272,8 +263,17 @@ function bindInputs(
         const thisBinding = binding;
         const thisEl = el;
 
-        return function (allowDeferred: boolean) {
-          valueChangeCallback(inputs, thisBinding, thisEl, allowDeferred);
+        // Historically speaking, this callback has only accepted a boolean value,
+        // but in recent versions it can also accept a input priority.
+        return function (priority: InputPolicyOpts["priority"] | boolean) {
+          const normalizedPriority =
+            typeof priority !== "boolean"
+              ? priority
+              : priority
+              ? "deferred"
+              : "immediate";
+
+          valueChangeCallback(inputs, thisBinding, thisEl, normalizedPriority);
         };
       })();
 

srcts/types/src/bindings/input/inputBinding.d.ts

@@ -1,3 +1,4 @@
+import type { EventPriority } from "../../inputPolicies/inputPolicy";
 import type { RatePolicyModes } from "../../inputPolicies/inputRateDecorator";
 import type { BindScope } from "../../shiny/bind";
 declare class InputBinding {
@@ -6,7 +7,7 @@ declare class InputBinding {
     getId(el: HTMLElement): string;
     getType(el: HTMLElement): string | null;
     getValue(el: HTMLElement): any;
-    subscribe(el: HTMLElement, callback: (value: boolean) => void): void;
+    subscribe(el: HTMLElement, callback: (value: EventPriority | boolean) => void): void;
     unsubscribe(el: HTMLElement): void;
     receiveMessage(el: HTMLElement, data: unknown): Promise<void> | void;
     getState(el: HTMLElement): unknown;