Binary Data Operations

/**
 * Converts a Uint8Array to a Base64 string
 * @param u8a - The Uint8Array to convert
 * @param urlsafe - If true, make the result URL-safe (uses - and _ instead of + and /)
 * @returns Base64 encoded string
 */
function fromUint8Array(u8a: Uint8Array, urlsafe?: boolean): string;

import { fromUint8Array } from "js-base64";

// Basic conversion
const bytes = new Uint8Array([100, 97, 110, 107, 111, 103, 97, 105]);
const encoded = fromUint8Array(bytes);
console.log(encoded); // "ZGFua29nYWk="

// URL-safe conversion
const urlSafe = fromUint8Array(bytes, true);
console.log(urlSafe); // "ZGFua29nYWk" (no padding)

// Converting image data or file bytes
const imageBytes = new Uint8Array([137, 80, 78, 71, 13, 10, 26, 10]); // PNG header
const imageB64 = fromUint8Array(imageBytes);
console.log(imageB64); // "iVBORw0KGgo="

// Working with typed arrays from File API or ArrayBuffer
const buffer = new ArrayBuffer(8);
const view = new Uint8Array(buffer);
view.set([72, 101, 108, 108, 111, 33, 33, 33]); // "Hello!!!"
const result = fromUint8Array(view);
console.log(result); // "SGVsbG8hISE="

/**
 * Converts a Base64 string to a Uint8Array
 * @param a - Base64 string (both normal and URL-safe are supported)
 * @returns Uint8Array containing the decoded binary data
 */
function toUint8Array(a: string): Uint8Array;

import { toUint8Array } from "js-base64";

// Basic conversion
const decoded = toUint8Array("ZGFua29nYWk=");
console.log(decoded); // Uint8Array(8) [100, 97, 110, 107, 111, 103, 97, 105]

// Convert to regular array if needed
const asArray = Array.from(decoded);
console.log(asArray); // [100, 97, 110, 107, 111, 103, 97, 105]

// Working with image data
const pngHeader = toUint8Array("iVBORw0KGgo=");
console.log(pngHeader); // Uint8Array [137, 80, 78, 71, 13, 10, 26, 10]

// URL-safe format (automatically detected)
const urlSafeDecoded = toUint8Array("ZGFua29nYWk");
console.log(urlSafeDecoded); // Same result as above

// Creating blobs from Base64 data
const b64Data = "SGVsbG8gV29ybGQh"; // "Hello World!"
const bytes = toUint8Array(b64Data);
const blob = new Blob([bytes], { type: 'text/plain' });

// Working with fetch responses
async function processB64Image(base64String) {
  const imageBytes = toUint8Array(base64String);
  const blob = new Blob([imageBytes], { type: 'image/png' });
  const url = URL.createObjectURL(blob);
  return url;
}

import { fromUint8Array, toUint8Array } from "js-base64";

// Original data
const original = new Uint8Array([1, 2, 3, 4, 5, 255, 128, 0]);

// Convert to Base64 and back
const encoded = fromUint8Array(original);
const decoded = toUint8Array(encoded);

// Verify integrity
console.log(original.every((byte, i) => byte === decoded[i])); // true

import { fromUint8Array, toUint8Array } from "js-base64";

// Reading a file as Base64
async function fileToBase64(file: File): Promise<string> {
  const arrayBuffer = await file.arrayBuffer();
  const uint8Array = new Uint8Array(arrayBuffer);
  return fromUint8Array(uint8Array);
}

// Converting Base64 back to file
function base64ToFile(base64: string, filename: string, mimeType: string): File {
  const uint8Array = toUint8Array(base64);
  return new File([uint8Array], filename, { type: mimeType });
}

import { fromUint8Array, toUint8Array } from "js-base64";

// ArrayBuffer to Base64
function arrayBufferToBase64(buffer: ArrayBuffer): string {
  const uint8Array = new Uint8Array(buffer);
  return fromUint8Array(uint8Array);
}

// Base64 to ArrayBuffer
function base64ToArrayBuffer(base64: string): ArrayBuffer {
  const uint8Array = toUint8Array(base64);
  return uint8Array.buffer.slice(uint8Array.byteOffset, uint8Array.byteOffset + uint8Array.byteLength);
}