fix(icon): throw error once per session if sprite icon fails to load (#1285)

* fix(icon): handle undefined sprite loading with console warning

* fix(icon): ensure sprite loading throws an error on failure

* fix(icon): refactor ErrorThrower to accept dynamic error messages

Author: bualoy-napat

packages/core/src/index.ts

@@ -47,6 +47,7 @@ export class LitElement extends BasicElement {
  */
 export { WarningNotice } from './notices/WarningNotice.js';
 export { DeprecationNotice } from './notices/DeprecationNotice.js';
+export { ErrorThrower } from './notices/ErrorThrower.js';
 
 /**
  * Export events

packages/core/src/notices/ErrorThrower.ts

@@ -0,0 +1,37 @@
+export class ErrorThrower {
+  /**
+   * Static list to track if any error message has been shown
+   * across the entire application session
+   */
+  private static readonly shownErrors = new Set<string>();
+
+  /**
+   * Checks if this error has been shown already
+   * @param {string} message The error message to check
+   * @returns {boolean} True if the error has been shown
+   */
+  public isShown(message: string): boolean {
+    return ErrorThrower.shownErrors.has(message);
+  }
+
+  /**
+   * Shows the error notice and marks it as shown
+   * @param {string} message The error message to throw
+   * @returns {void}
+   */
+  public throw(message: string): void {
+    ErrorThrower.shownErrors.add(message);
+    throw new Error(message);
+  }
+
+  /**
+   * Shows the error notice only once per application session
+   * @param {string} message The error message to throw
+   * @returns {void}
+   */
+  public once(message: string): void {
+    if (!this.isShown(message)) {
+      this.throw(message);
+    }
+  }
+}

packages/elements/src/icon/index.ts

@@ -4,6 +4,7 @@ import {
   BasicElement,
   CSSResultGroup,
   DeprecationNotice,
+  ErrorThrower,
   PropertyValues,
   SVGTemplateResult,
   TemplateResult,
@@ -37,6 +38,8 @@ const EmptyTemplate = svg``;
  */
 export const iconTemplateCache = new Map<string, Promise<SVGTemplateResult>>();
 
+const errorThrower = new ErrorThrower();
+
 @customElement('ef-icon')
 export class Icon extends BasicElement {
   /**
@@ -230,7 +233,9 @@ export class Icon extends BasicElement {
     } else if (isUrl(iconProperty) || IconLoader.isPrefixResolved) {
       void this.loadAndRenderIcon(iconProperty);
     } else {
-      void this.loadAndRenderSpriteIcon(iconProperty);
+      void this.loadAndRenderSpriteIcon(iconProperty).catch((error) => {
+        errorThrower.once(String(error));
+      });
     }
   }