onerror -> handleError

packages/svelte/src/index.d.ts

@@ -340,9 +340,9 @@ export type MountOptions<Props extends Record<string, any> = Record<string, any>
 	intro?: boolean;
 	/**
 	 * A function that transforms errors caught by error boundaries before they are passed to the `failed` snippet.
-	 * This is used by SvelteKit to apply `handleError`. Defaults to the identity function on the client, and to throwing on the server.
+	 * Defaults to the identity function.
 	 */
-	onerror?: (error: unknown) => unknown | Promise<unknown>;
+	handleError?: (error: unknown) => unknown | Promise<unknown>;
 } & ({} extends Props
 	? {
 			/**

packages/svelte/src/internal/client/dom/blocks/boundary.js

@@ -59,11 +59,11 @@ var flags = EFFECT_TRANSPARENT | EFFECT_PRESERVED | BOUNDARY_EFFECT;
  * @param {TemplateNode} node
  * @param {BoundaryProps} props
  * @param {((anchor: Node) => void)} children
- * @param {((error: unknown) => unknown) | undefined} [onerror_transform]
+ * @param {((error: unknown) => unknown) | undefined} [transform_error]
  * @returns {void}
  */
-export function boundary(node, props, children, onerror_transform) {
-	new Boundary(node, props, children, onerror_transform);
+export function boundary(node, props, children, transform_error) {
+	new Boundary(node, props, children, transform_error);
 }
 
 export class Boundary {
@@ -73,11 +73,11 @@ export class Boundary {
 	is_pending = false;
 
 	/**
-	 * API-level onerror transform function. Transforms errors before they reach the `failed` snippet.
+	 * API-level handleError transform function. Transforms errors before they reach the `failed` snippet.
 	 * Inherited from parent boundary, or defaults to identity.
 	 * @type {(error: unknown) => unknown}
 	 */
-	onerror_transform;
+	transform_error;
 
 	/** @type {TemplateNode} */
 	#anchor;
@@ -146,18 +146,18 @@ export class Boundary {
 	 * @param {TemplateNode} node
 	 * @param {BoundaryProps} props
 	 * @param {((anchor: Node) => void)} children
-	 * @param {((error: unknown) => unknown) | undefined} [onerror_transform]
+	 * @param {((error: unknown) => unknown) | undefined} [transform_error]
 	 */
-	constructor(node, props, children, onerror_transform) {
+	constructor(node, props, children, transform_error) {
 		this.#anchor = node;
 		this.#props = props;
 		this.#children = children;
 
 		this.parent = /** @type {Effect} */ (active_effect).b;
 
-		// Inherit onerror_transform from parent boundary, or use the provided one, or default to identity
-		this.onerror_transform =
-			onerror_transform ?? (this.parent ? this.parent.onerror_transform : (e) => e);
+		// Inherit transform_error from parent boundary, or use the provided one, or default to identity
+		this.transform_error =
+			transform_error ?? (this.parent ? this.parent.transform_error : (e) => e);
 
 		this.is_pending = !!this.#props.pending;
 
@@ -522,11 +522,11 @@ export class Boundary {
 		};
 
 		queue_micro_task(() => {
-			// Run the error through the API-level onerror transform (e.g. SvelteKit's handleError)
+			// Run the error through the API-level handleError transform (e.g. SvelteKit's handleError)
 			/** @type {unknown} */
 			var result;
 			try {
-				result = this.onerror_transform(error);
+				result = this.transform_error(error);
 			} catch (e) {
 				invoke_error_boundary(e, this.#effect && this.#effect.parent);
 				return;
@@ -537,7 +537,7 @@ export class Boundary {
 				typeof result === 'object' &&
 				typeof (/** @type {any} */ (result).then) === 'function'
 			) {
-				// onerror returned a Promise — wait for it
+				// handleError returned a Promise — wait for it
 				/** @type {any} */ (result).then(
 					/** @param {unknown} transformed_error */
 					(transformed_error) => handle_error_result(transformed_error),

packages/svelte/src/internal/client/render.js

@@ -81,7 +81,7 @@ export function mount(component, options) {
  *  	context?: Map<any, any>;
  * 		intro?: boolean;
  * 		recover?: boolean;
- *		onerror?: (error: unknown) => unknown;
+ *		handleError?: (error: unknown) => unknown;
  * 	} : {
  * 		target: Document | Element | ShadowRoot;
  * 		props: Props;
@@ -89,7 +89,7 @@ export function mount(component, options) {
  *  	context?: Map<any, any>;
  * 		intro?: boolean;
  * 		recover?: boolean;
- *		onerror?: (error: unknown) => unknown;
+ *		handleError?: (error: unknown) => unknown;
  * 	}} options
  * @returns {Exports}
  */
@@ -160,7 +160,10 @@ const document_listeners = new Map();
  * @param {MountOptions} options
  * @returns {Exports}
  */
-function _mount(Component, { target, anchor, props = {}, events, context, intro = true, onerror }) {
+function _mount(
+	Component,
+	{ target, anchor, props = {}, events, context, intro = true, handleError }
+) {
 	init_operations();
 
 	/** @type {Set<string>} */
@@ -243,7 +246,7 @@ function _mount(Component, { target, anchor, props = {}, events, context, intro
 
 				pop();
 			},
-			onerror
+			handleError
 		);
 
 		return () => {

packages/svelte/src/internal/server/index.js

@@ -56,7 +56,7 @@ export function element(renderer, tag, attributes_fn = noop, children_fn = noop)
  * Takes a component and returns an object with `body` and `head` properties on it, which you can use to populate the HTML when server-rendering your app.
  * @template {Record<string, any>} Props
  * @param {Component<Props> | ComponentType<SvelteComponent<Props>>} component
- * @param {{ props?: Omit<Props, '$$slots' | '$$events'>; context?: Map<any, any>; idPrefix?: string; csp?: Csp; onerror?: (error: unknown) => unknown }} [options]
+ * @param {{ props?: Omit<Props, '$$slots' | '$$events'>; context?: Map<any, any>; idPrefix?: string; csp?: Csp; handleError?: (error: unknown) => unknown }} [options]
  * @returns {RenderOutput}
  */
 export function render(component, options = {}) {

packages/svelte/src/internal/server/renderer.js

@@ -52,7 +52,7 @@ export class Renderer {
 	/**
 	 * If set, this renderer is an error boundary. When async collection
 	 * of the children fails, the failed snippet is rendered instead.
-	 * @type {{ failed: (renderer: Renderer, error: unknown, reset: () => void) => void; onerror: (error: unknown) => unknown } | null}
+	 * @type {{ failed: (renderer: Renderer, error: unknown, reset: () => void) => void; handleError: (error: unknown) => unknown } | null}
 	 */
 	#boundary = null;
 
@@ -224,7 +224,7 @@ export class Renderer {
 
 	/**
 	 * Render children inside an error boundary. If the children throw and the API-level
-	 * `onerror` transform handles the error (doesn't re-throw), the `failed` snippet is
+	 * `handleError` transform handles the error (doesn't re-throw), the `failed` snippet is
 	 * rendered instead. Otherwise the error propagates.
 	 *
 	 * @param {{ failed?: (renderer: Renderer, error: unknown, reset: () => void) => void }} props
@@ -240,7 +240,7 @@ export class Renderer {
 		if (props.failed) {
 			child.#boundary = {
 				failed: props.failed,
-				onerror: this.global.onerror
+				handleError: this.global.handleError
 			};
 		}
 
@@ -273,7 +273,7 @@ export class Renderer {
 
 			if (!failed_snippet) throw error;
 
-			const result = this.global.onerror(error);
+			const result = this.global.handleError(error);
 
 			if (result instanceof Promise) {
 				if (this.global.mode === 'sync') {
@@ -684,9 +684,9 @@ export class Renderer {
 						content.head += boundary_content.head;
 						content.body += boundary_content.body;
 					} catch (error) {
-						const { failed, onerror } = item.#boundary;
+						const { failed, handleError } = item.#boundary;
 
-						let transformed = await onerror(error);
+						let transformed = await handleError(error);
 
 						// Render the failed snippet instead of the partial children content
 						const failed_renderer = new Renderer(item.global, item);
@@ -728,7 +728,7 @@ export class Renderer {
 	 * @template {Record<string, any>} Props
 	 * @param {'sync' | 'async'} mode
 	 * @param {import('svelte').Component<Props>} component
-	 * @param {{ props?: Omit<Props, '$$slots' | '$$events'>; context?: Map<any, any>; idPrefix?: string; csp?: Csp; onerror?: (error: unknown) => unknown }} options
+	 * @param {{ props?: Omit<Props, '$$slots' | '$$events'>; context?: Map<any, any>; idPrefix?: string; csp?: Csp; handleError?: (error: unknown) => unknown }} options
 	 * @returns {Renderer}
 	 */
 	static #open_render(mode, component, options) {
@@ -737,7 +737,7 @@ export class Renderer {
 				mode,
 				options.idPrefix ? options.idPrefix + '-' : '',
 				options.csp,
-				options.onerror
+				options.handleError
 			)
 		);
 
@@ -851,11 +851,11 @@ export class SSRState {
 	css = new Set();
 
 	/**
-	 * `onerror` transform passed to `render`. Called when an error boundary catches an error.
+	 * `handleError` transform passed to `render`. Called when an error boundary catches an error.
 	 * Throws by default if unset in `render`.
 	 * @type {(error: unknown) => unknown}
 	 */
-	onerror;
+	handleError;
 
 	/** @type {{ path: number[], value: string }} */
 	#title = { path: [], value: '' };
@@ -864,14 +864,14 @@ export class SSRState {
 	 * @param {'sync' | 'async'} mode
 	 * @param {string} id_prefix
 	 * @param {Csp} csp
-	 * @param {((error: unknown) => unknown) | undefined} [onerror]
+	 * @param {((error: unknown) => unknown) | undefined} [handleError]
 	 */
-	constructor(mode, id_prefix = '', csp = { hash: false }, onerror) {
+	constructor(mode, id_prefix = '', csp = { hash: false }, handleError) {
 		this.mode = mode;
 		this.csp = { ...csp, script_hashes: [] };
 
-		this.onerror =
-			onerror ??
+		this.handleError =
+			handleError ??
 			((error) => {
 				throw error;
 			});

packages/svelte/src/server/index.d.ts

@@ -17,7 +17,7 @@ export function render<
 					context?: Map<any, any>;
 					idPrefix?: string;
 					csp?: Csp;
-					onerror?: (error: unknown) => unknown | Promise<unknown>;
+					handleError?: (error: unknown) => unknown | Promise<unknown>;
 				}
 			]
 		: [
@@ -27,7 +27,7 @@ export function render<
 					context?: Map<any, any>;
 					idPrefix?: string;
 					csp?: Csp;
-					onerror?: (error: unknown) => unknown | Promise<unknown>;
+					handleError?: (error: unknown) => unknown | Promise<unknown>;
 				}
 			]
 ): RenderOutput;

packages/svelte/tests/runtime-legacy/shared.ts

@@ -101,7 +101,7 @@ export interface RuntimeTest<Props extends Record<string, any> = Record<string,
 	expect_unhandled_rejections?: boolean;
 	withoutNormalizeHtml?: boolean | 'only-strip-comments';
 	recover?: boolean;
-	onerror?: (error: unknown) => unknown;
+	handleError?: (error: unknown) => unknown;
 }
 
 declare global {
@@ -365,7 +365,7 @@ async function run_test_variant(
 			const render_result = render(SsrSvelteComponent, {
 				props: config.server_props ?? config.props ?? {},
 				idPrefix: config.id_prefix,
-				onerror: config.onerror
+				handleError: config.handleError
 			});
 			const rendered =
 				variant === 'async-ssr' || (variant === 'hydrate' && compileOptions.experimental?.async)
@@ -465,7 +465,7 @@ async function run_test_variant(
 						props,
 						intro: config.intro,
 						recover: config.recover ?? false,
-						onerror: config.onerror
+						handleError: config.handleError
 					});
 				}
 			} else {

packages/svelte/tests/runtime-runes/samples/async-error-boundary/_config.js

@@ -4,7 +4,7 @@ import { test } from '../../test';
 export default test({
 	mode: ['hydrate', 'async-server', 'client'],
 	ssrHtml: '<p>caught: error</p>',
-	onerror: (error) => {
+	handleError: (error) => {
 		if (error !== 'catch me') throw 'wrong error object';
 		return 'error';
 	},

packages/svelte/tests/runtime-runes/samples/error-boundary-26/_config.js

@@ -4,7 +4,7 @@ import { test } from '../../test';
 export default test({
 	mode: ['hydrate', 'async-server', 'client'],
 	ssrHtml: '<p>caught: error</p>',
-	onerror: (error) => {
+	handleError: (error) => {
 		if (error !== 'catch me') throw 'wrong error object';
 		return 'error';
 	},

packages/svelte/tests/server-side-rendering/samples/boundary-error-no-failed-snippet/_config.js

@@ -1,8 +1,8 @@
 import { test } from '../../test';
 
 export default test({
-	// onerror handles the error, but there's no failed snippet.
+	// handleError handles the error, but there's no failed snippet.
 	// The error should still propagate because there's nothing to render instead.
-	onerror: () => 'you will not see me',
+	handleError: () => 'you will not see me',
 	error: 'component error'
 });

packages/svelte/tests/server-side-rendering/samples/boundary-error-no-onerror/_config.js

@@ -1,6 +1,6 @@
 import { test } from '../../test';
 
 export default test({
-	// No onerror - by default the server throws, so the error should propagate.
+	// No handleError - by default the server throws, so the error should propagate.
 	error: 'component error'
 });

packages/svelte/tests/server-side-rendering/samples/boundary-error-with-onerror/_config.js

@@ -1,10 +1,10 @@
 import { test } from '../../test';
 
 export default test({
-	// boundary with failed snippet exists, so onerror should transform the error
-	onerror: (error) => {
+	// boundary with failed snippet exists, so handleError should transform the error
+	handleError: (error) => {
 		if (/** @type {Error} */ (error).message !== 'you are not supposed to see this message') {
-			return 'wrong object passed to onerror';
+			return 'wrong object passed to handleError';
 		}
 		return 'component error';
 	}

packages/svelte/tests/server-side-rendering/test.ts

@@ -24,7 +24,7 @@ interface SSRTest extends BaseTest {
 	error?: string;
 	csp?: { nonce: string } | { hash: true };
 	script_hashes?: string[];
-	onerror?: (error: unknown) => unknown;
+	handleError?: (error: unknown) => unknown;
 }
 
 // TODO remove this shim when we can
@@ -86,7 +86,7 @@ const { test, run } = suite_with_variants<SSRTest, 'sync' | 'async', CompileOpti
 				props: config.props || {},
 				idPrefix: config.id_prefix,
 				csp: config.csp,
-				onerror: config.onerror
+				handleError: config.handleError
 			});
 			rendered = is_async ? await render_result : render_result;
 			// we need to access these inside the try-catch otherwise errors in the script tag are not caught

packages/svelte/types/index.d.ts

@@ -339,9 +339,9 @@ declare module 'svelte' {
 		intro?: boolean;
 		/**
 		 * A function that transforms errors caught by error boundaries before they are passed to the `failed` snippet.
-		 * This is used by SvelteKit to apply `handleError`. Defaults to the identity function on the client, and to throwing on the server.
+		 * Defaults to the identity function.
 		 */
-		onerror?: (error: unknown) => unknown | Promise<unknown>;
+		handleError?: (error: unknown) => unknown | Promise<unknown>;
 	} & ({} extends Props
 		? {
 				/**
@@ -547,7 +547,7 @@ declare module 'svelte' {
 		context?: Map<any, any>;
 		intro?: boolean;
 		recover?: boolean;
-		onerror: (error: unknown) => unknown;
+		handleError?: (error: unknown) => unknown;
 	} : {
 		target: Document | Element | ShadowRoot;
 		props: Props;
@@ -555,7 +555,7 @@ declare module 'svelte' {
 		context?: Map<any, any>;
 		intro?: boolean;
 		recover?: boolean;
-		onerror?: (error: unknown) => unknown;
+		handleError?: (error: unknown) => unknown;
 	}): Exports;
 	/**
 	 * Unmounts a component that was previously mounted using `mount` or `hydrate`.
@@ -2567,7 +2567,7 @@ declare module 'svelte/server' {
 						context?: Map<any, any>;
 						idPrefix?: string;
 						csp?: Csp;
-						onerror?: (error: unknown) => unknown | Promise<unknown>;
+						handleError?: (error: unknown) => unknown | Promise<unknown>;
 					}
 				]
 			: [
@@ -2577,7 +2577,7 @@ declare module 'svelte/server' {
 						context?: Map<any, any>;
 						idPrefix?: string;
 						csp?: Csp;
-						onerror?: (error: unknown) => unknown | Promise<unknown>;
+						handleError?: (error: unknown) => unknown | Promise<unknown>;
 					}
 				]
 	): RenderOutput;