Encoding

Global functions for base64 and percent-encoding (URL encoding). Available without any import.

btoa(str)

Encode a string to base64.

const encoded = btoa("hello world");
// "aGVsbG8gd29ybGQ="

const auth = "Basic " + btoa(username + ":" + password);

atob(str)

Decode a base64 string.

const decoded = atob("aGVsbG8gd29ybGQ=");
// "hello world"

encodeURIComponent(str)

Percent-encode a string per RFC 3986. Unreserved characters (A-Z a-z 0-9 - _ . ~) are left as-is; everything else is encoded as %XX.

const q = encodeURIComponent("hello world & foo=bar");
// "hello%20world%20%26%20foo%3Dbar"

const url = "https://api.example.com/search?q=" + encodeURIComponent(userInput);

decodeURIComponent(str)

Decode a percent-encoded string.

const s = decodeURIComponent("hello%20world%20%26%20foo%3Dbar");
// "hello world & foo=bar"

Example

const token = btoa("user:pass");
console.log(token); // "dXNlcjpwYXNz"
console.log(atob(token)); // "user:pass"

const params = "name=" + encodeURIComponent("John Doe") + "&city=" + encodeURIComponent("New York");
// "name=John%20Doe&city=New%20York"

Native Implementation

API	Maps to
btoa()	cs_btoa() in c_bridges/base64-bridge.c
atob()	cs_atob() in c_bridges/base64-bridge.c
encodeURIComponent()	cs_encode_uri_component() in c_bridges/uri-bridge.c
decodeURIComponent()	cs_decode_uri_component() in c_bridges/uri-bridge.c