Convert a string to bytes and back

We start with a plain string.

const text = "Hello";

To convert to a Uint8Array of UTF-8 bytes, use TextEncoder.

const bytes = new TextEncoder().encode(text);
console.log(bytes); // Uint8Array(5) [ 72, 101, 108, 108, 111 ]

To convert back, use TextDecoder.

console.log(new TextDecoder().decode(bytes)); // Hello

To get an ArrayBuffer, encode first and take the underlying buffer.

const buffer = new TextEncoder().encode(text).buffer;
console.log(buffer.byteLength); // 5

To convert to a Blob, pass the string directly. The Blob constructor encodes it as UTF-8 for you.

const blob = new Blob([text]);
console.log(blob.size); // 5

To convert to a ReadableStream, the most direct route is through a Blob.

const stream = new Blob([text]).stream();
console.log(await new Response(stream).text()); // Hello

To convert to a base64 string, encode to bytes and use the built-in toBase64 method.

const base64 = new TextEncoder().encode(text).toBase64();
console.log(base64); // SGVsbG8=

To decode base64 back to a string, combine fromBase64 and TextDecoder.

console.log(new TextDecoder().decode(Uint8Array.fromBase64(base64))); // Hello

Run this example locally using the Ende CLI:

ende run https://docs.ende.sh/examples/scripts/convert_string.ts

Additional resources

• MDN: TextEncoder
• MDN: TextDecoder