Function base64ToArrayBuffer

packages/ai-utils/src/base64.ts:61–83

(base64: string)

 * Decode a base64 string into an `ArrayBuffer`.
 */
export function base64ToArrayBuffer(base64: string): ArrayBuffer {
  // eslint-disable-next-line no-restricted-syntax -- feature-detecting Uint8Array.fromBase64 Stage-3 proposal not yet in lib.es types
  const fast = (Uint8Array as unknown as Uint8ArrayWithBase64).fromBase64
  if (typeof fast === 'function') {
    return fast(base64).buffer as ArrayBuffer
  }

  if (typeof atob === 'function') {
    const binary = atob(base64)
    const bytes = new Uint8Array(binary.length)
    for (let i = 0; i < binary.length; i++) {
      bytes[i] = binary.charCodeAt(i)
    }
    return bytes.buffer
  }

  if (typeof Buffer !== 'undefined' && typeof Buffer.from === 'function') {
    const buf = Buffer.from(base64, 'base64')
    return buf.buffer.slice(buf.byteOffset, buf.byteOffset + buf.byteLength)
  }

  throw new Error('No base64 decoder available in this environment.')
}