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const chr = 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/';const map = new Array<number>(256);
for (let i = 0, count = chr.length; i < count; i++) {  map[chr.charCodeAt(i)] = i;}
/** * @name base64Decode * @description * A base64Decoding function that operates in all environments. Unlike decoding * from Buffer (Node.js only) or atob (browser-only) this implementation is * slightly slower, but it is platform independent. * * For our usage, since we have access to the static final size (where used), we * decode to a specified output buffer. This also means we have applied a number * of optimizations based on this - checking output position instead of chars. */export function base64Decode (data: string, out: Uint8Array): Uint8Array {  let byte = 0;  let bits = 0;  let pos = -1;
  for (let i = 0, count = out.length; pos < count; i++) {    // each character represents 6 bits    byte = (byte << 6) | map[data.charCodeAt(i)];
    // each byte needs to contain 8 bits    if ((bits += 6) >= 8) {      out[++pos] = (byte >>> (bits -= 8)) & 0xff;    }  }
  return out;}