Angular - Download Image as Base64

image.service.ts

  async downloadImageToBase64(imageUrl: string) {
    const resp: Blob = await this.httpClient.get(imageUrl,
      {
        headers: {
          accept: 'image/png, image/webp, image/jpeg, image/gif'
        },
        responseType: 'blob'
      }).toPromise();
    return (await this.convertBlobToBase64(resp)) as string;
  }
  
  private convertBlobToBase64(blob: Blob) {
    return new Promise((resolve, reject) => {
      const reader = new FileReader();
      reader.onerror = reject;
      reader.onload = () => {
        resolve(reader.result);
      };
      return reader.readAsDataURL(blob);
    });
  }