Text representation conversion

text-manipulation.ts

// Text representation conversion

const convertStreamToBase64 = (buffer: ArrayBuffer | Uint8Array): string =>
  window.btoa(new Uint8Array(buffer).reduce((a, b) => a + String.fromCharCode(b), ''));

const convertBase64ToStream = <T extends ArrayBuffer | Uint8Array>(base64: string, mimeType?: string): T => {
  let sanitized = base64;
  if (mimeType) sanitized = sanitized.replace(`data:${mimeType};base64,`, '');

  const bin = window.atob(sanitized);
  const buffer = new ArrayBuffer(bin.length);
  const bufferView = new Uint8Array(buffer);

  for (let i = 0; i < bin.length; i++) bufferView[i] = bin.charCodeAt(i);

  return buffer as T;
}

// Encoding / Decoding

const encode = (data: string) => new TextEncoder().encode(data);
const decode = (buffer: ArrayBuffer) => new TextDecoder().decode(buffer);

export default {
  convertStreamToBase64,
  convertBase64ToStream,
  encode,
  decode
}