chore: add hmr compiler flag (#11112)

* chore: add hmr compiler flag

* lint

packages/svelte/src/compiler/types/index.d.ts

@@ -178,6 +178,12 @@ export interface CompileOptions extends ModuleCompileOptions {
 	 * @default null
 	 */
 	cssOutputFilename?: string;
+	/**
+	 * If `true`, compiles components with hot reloading support.
+	 *
+	 * @default false
+	 */
+	hmr?: boolean;
 }
 
 export interface ModuleCompileOptions {
@@ -225,6 +231,7 @@ export type ValidatedCompileOptions = ValidatedModuleCompileOptions &
 		legacy: Required<Required<CompileOptions>['legacy']>;
 		runes: CompileOptions['runes'];
 		customElementOptions: SvelteOptions['customElement'];
+		hmr: CompileOptions['hmr'];
 	};
 
 export type DeclarationKind =

packages/svelte/src/compiler/validate-options.js

@@ -95,6 +95,8 @@ export const validate_component_options =
 
 			runes: boolean(undefined),
 
+			hmr: boolean(false),
+
 			sourcemap: validator(undefined, (input) => {
 				// Source maps can take on a variety of values, including string, JSON, map objects from magic-string and source-map,
 				// so there's no good way to check type validity here

packages/svelte/types/index.d.ts

@@ -670,6 +670,12 @@ declare module 'svelte/compiler' {
 		 * @default null
 		 */
 		cssOutputFilename?: string;
+		/**
+		 * If `true`, compiles components with hot reloading support.
+		 *
+		 * @default false
+		 */
+		hmr?: boolean;
 	}
 
 	interface ModuleCompileOptions {
@@ -2449,6 +2455,12 @@ declare module 'svelte/types/compiler/interfaces' {
 		 * @default null
 		 */
 		cssOutputFilename?: string;
+		/**
+		 * If `true`, compiles components with hot reloading support.
+		 *
+		 * @default false
+		 */
+		hmr?: boolean;
 	}
 
 	interface ModuleCompileOptions {