temp: first implementation

app/services/harfbuzz.ts

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+import Service from '@ember/service';
+import hb from 'harfbuzzjs/hbjs';
+import type { HBInstance } from 'harfbuzzjs/hbjs';
+
+export default class HarfbuzzService extends Service {
+  declare hb: HBInstance;
+
+  loadWASMPromise: undefined | Promise<void> = undefined;
+
+  async loadWASM() {
+    if (!this.loadWASMPromise) {
+      this.loadWASMPromise = this._loadWASM();
+    }
+
+    await this.loadWASMPromise;
+  }
+
+  async _loadWASM() {
+    const result = await WebAssembly.instantiateStreaming(fetch('/hb.wasm'));
+    this.hb = hb(result.instance);
+  }
+}
+
+declare module '@ember/service' {
+  interface Registry {
+    harfbuzz: HarfbuzzService;
+  }
+}

types/harfbuzzjs.d.ts

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+declare module 'harfbuzzjs/hbjs' {
+  type Direction = 'ltr' | 'rtl' | 'ttb' | 'btt';
+  type BufferFlag =
+    | 'BOT'
+    | 'EOT'
+    | 'PRESERVE_DEFAULT_IGNORABLES'
+    | 'REMOVE_DEFAULT_IGNORABLES'
+    | 'DO_NOT_INSERT_DOTTED_CIRCLE'
+    | 'PRODUCE_UNSAFE_TO_CONCAT';
+
+  type HBBlob = unknown;
+
+  export interface HBFace {
+    upem: number; //units per em
+    reference_table(table: string): Uint8Array;
+    getAxisInfos(): Record<string, { min: number; default: number; max: number }>;
+    collectUnicodes(): Uint32Array;
+    destroy(): void;
+  }
+
+  export interface SVGPathSegment {
+    type: 'M' | 'L' | 'Q' | 'C' | 'Z';
+    values: number[];
+  }
+
+  export type BufferContent = {
+    g: number; //The glyph ID
+    cl: number; //The cluster ID
+    ax: number; //Advance width (width to advance after this glyph is painted)
+    ay: number; //Advance height (height to advance after this glyph is painted)
+    dx: number; //X displacement (adjustment in X dimension when painting this glyph)
+    dy: number; //Y displacement (adjustment in Y dimension when painting this glyph)
+    flags: number; // Glyph flags like `HB_GLYPH_FLAG_UNSAFE_TO_BREAK` (0x1)
+  }[];
+
+  export interface HBFont {
+    glyphName(glyphId: number): string;
+    glyphToPath(glyphId: number): string;
+    glyphToJson(glyphId: number): SVGPathSegment[];
+    setScale(xScale: number, yScale: number): void;
+    setVariations(variations: Record<string, string | number | boolean>): void;
+    destroy(): void;
+  }
+
+  interface HBBuffer {
+    addText(text: string): void;
+    guessSegmentProperties(): void;
+    setDirection(dir: Direction): void;
+    setFlags(flags: BufferFlag[]): void;
+    setLanguage(language: string): void;
+    setScript(script: string): void;
+    setClusterLevel(level: number): void;
+    json(): BufferContent;
+    destroy(): void;
+  }
+
+  export interface HBInstance {
+    createBlob(buffer: ArrayBuffer): HBBlob;
+    createFace(blob: HBBlob, fontIndex: number): HBFace;
+    createFont(face: HBFace): HBFont;
+    createBuffer(): HBBuffer;
+    shape(font: HBFont, buffer: HBBuffer): void;
+  }
+
+  const hb: (instance: WebAssembly.Instance) => HBInstance;
+
+  export default hb;
+}