refactor: convert icon-factory.js to typescript

ui/helpers/utils/icon-factory.ts

@@ -0,0 +1,141 @@
+import { isValidHexAddress } from '../../../shared/modules/hexstring-utils';
+
+/**
+ * Defines the metadata for a token including optional icon URL.
+ */
+type TokenMetadata = {
+  iconUrl: string;
+};
+
+/**
+ * A factory for generating icons for cryptocurrency addresses using Jazzicon or predefined token metadata.
+ */
+class IconFactory {
+  /**
+   * Function to generate a Jazzicon SVG element.
+   */
+  jazzicon: (diameter: number, seed: number) => SVGSVGElement;
+
+  /**
+   * Cache for storing generated SVG elements to avoid re-rendering.
+   */
+  cache: { [key: string]: SVGSVGElement };
+
+  /**
+   * Constructs an IconFactory instance with a given Jazzicon function.
+   *
+   * @param jazzicon - A function that returns a Jazzicon SVG given a diameter and seed.
+   */
+  constructor(jazzicon: (diameter: number, seed: number) => SVGSVGElement) {
+    this.jazzicon = jazzicon;
+    this.cache = {};
+  }
+
+  /**
+   * Generates an icon for a given address. Returns a predefined image or generates a new Jazzicon.
+   *
+   * @param address - The cryptocurrency address to generate the icon for.
+   * @param diameter - The diameter of the icon to be generated.
+   * @param tokenMetadata - Metadata containing optional icon URL for predefined icons.
+   * @returns An HTML element representing the icon.
+   */
+  iconForAddress(
+    address: string,
+    diameter: number,
+    tokenMetadata?: Partial<TokenMetadata>,
+  ): HTMLElement | SVGSVGElement {
+    if (iconExistsFor(address, tokenMetadata)) {
+      return imageElFor(tokenMetadata);
+    }
+
+    return this.generateIdenticonSvg(address, diameter);
+  }
+
+  /**
+   * Generates or retrieves from cache a Jazzicon SVG for a given address and diameter.
+   *
+   * @param address - The cryptocurrency address for the identicon.
+   * @param diameter - The diameter of the identicon.
+   * @returns A Jazzicon SVG element.
+   */
+  generateIdenticonSvg(address: string, diameter: number): SVGSVGElement {
+    const cacheId = `${address}:${diameter}`;
+    const identicon: SVGSVGElement =
+      this.cache[cacheId] ||
+      (this.cache[cacheId] = this.generateNewIdenticon(address, diameter));
+    const cleanCopy: SVGSVGElement = identicon.cloneNode(true) as SVGSVGElement;
+    return cleanCopy;
+  }
+
+  /**
+   * Generates a new Jazzicon SVG for a given address and diameter.
+   *
+   * @param address - The cryptocurrency address for the identicon.
+   * @param diameter - The diameter of the identicon.
+   * @returns A new Jazzicon SVG element.
+   */
+  generateNewIdenticon(address: string, diameter: number): SVGSVGElement {
+    const numericRepresentation = jsNumberForAddress(address);
+    const identicon = this.jazzicon(diameter, numericRepresentation);
+    return identicon;
+  }
+}
+
+let iconFactory: IconFactory | undefined;
+
+/**
+ * Generates or retrieves an existing IconFactory instance.
+ *
+ * @param jazzicon - A function that returns a Jazzicon SVG given a diameter and seed.
+ * @returns An IconFactory instance.
+ */
+export default function iconFactoryGenerator(
+  jazzicon: (diameter: number, seed: number) => SVGSVGElement,
+): IconFactory {
+  if (!iconFactory) {
+    iconFactory = new IconFactory(jazzicon);
+  }
+  return iconFactory;
+}
+
+/**
+ * Determines if an icon already exists for a given address based on token metadata.
+ *
+ * @param address - The cryptocurrency address.
+ * @param tokenMetadata - Metadata containing optional icon URL.
+ * @returns True if an icon exists, otherwise false.
+ */
+function iconExistsFor(
+  address: string,
+  tokenMetadata?: Partial<TokenMetadata>,
+): tokenMetadata is TokenMetadata {
+  if (!tokenMetadata?.iconUrl) {
+    return false;
+  }
+  return isValidHexAddress(address, { allowNonPrefixed: false });
+}
+
+/**
+ * Creates an HTMLImageElement for a given token metadata.
+ *
+ * @param tokenMetadata - Metadata containing the icon URL. Defaults to an empty object.
+ * @returns An HTMLImageElement with the source set to the icon URL.
+ */
+function imageElFor(tokenMetadata: TokenMetadata): HTMLImageElement {
+  const img = document.createElement('img');
+  img.src = tokenMetadata.iconUrl;
+  img.style.width = '100%';
+  return img;
+}
+
+/**
+ * Converts a hexadecimal address into a numerical seed.
+ *
+ * @param address - The cryptocurrency address.
+ * @returns A numerical seed derived from the address.
+ */
+function jsNumberForAddress(address: string): number {
+  const addr = address.slice(2, 10);
+  const seed = parseInt(addr, 16);
+  return seed;
+}