[New] Uint8Array.prototype.toBase64: add omitPadding option, per …

…spec

See tc39/proposal-arraybuffer-base64#60

.eslintrc

@@ -16,9 +16,9 @@
 		"multiline-comment-style": "off",
 		"new-cap": ["error", {
 			"capIsNewExceptions": [
+				"DetachArrayBuffer",
 				"FromBase64",
 				"FromHex",
-				"DetachArrayBuffer",
 				"Get",
 				"GetIntrinsic",
 				"GetOptionsObject",
@@ -29,6 +29,7 @@
 				"SetUint8ArrayBytes",
 				"SetValueInBuffer",
 				"StringPad",
+				"ToBoolean",
 				"TypedArrayLength",
 				"ValidateUint8Array",
 			],

Uint8Array.prototype.toBase64/implementation.js

@@ -6,6 +6,7 @@ var Get = require('es-abstract/2024/Get');
 var GetOptionsObject = require('../aos/GetOptionsObject');
 var GetUint8ArrayBytes = require('../aos/GetUint8ArrayBytes');
 var ValidateUint8Array = require('../aos/ValidateUint8Array');
+var ToBoolean = require('es-abstract/2024/ToBoolean');
 
 var alphabetFromIdentifier = require('../aos/helpers/alphabetFromIdentifier');
 
@@ -31,17 +32,19 @@ module.exports = function toBase64() {
 		throw new $TypeError('Assertion failed: `alphabet` is not `\'base64\'` or `\'base64url\'`: ' + (typeof alphabet === 'string' ? alphabet : typeof alphabet)); // step 6
 	}
 
+	var omitPadding = ToBoolean(Get(opts, 'omitPadding')); // step 7
+
 	// eslint-disable-next-line no-unused-vars
-	var toEncode = GetUint8ArrayBytes(O); // step 7
+	var toEncode = GetUint8ArrayBytes(O); // step 8
 
-	// if (alphabet === 'base64') { // step 8
+	// if (alphabet === 'base64') { // step 9
 	// 		a. Let outAscii be the sequence of code points which results from encoding toEncode according to the base64 encoding specified in section 4 of RFC 4648.
-	// } else { // step 9
+	// } else { // step 10
 	// 		a. Assert: alphabet is "base64url".
 	// 		b. Let outAscii be the sequence of code points which results from encoding toEncode according to the base64url encoding specified in section 5 of RFC 4648.
 	// }
 
-	// return CodePointsToString(outAscii); // step 9
+	// return CodePointsToString(outAscii); // step 11
 
 	// code adapted from https://github.com/tc39/proposal-arraybuffer-base64/blob/22228812214d5a1c2966cd626f43be3576e79290/playground/polyfill-core.mjs
 	var lookup = alphabetFromIdentifier(alphabet);
@@ -61,12 +64,12 @@ module.exports = function toBase64() {
 		result += $charAt(lookup, (triplet >> 18) & 63)
 			+ $charAt(lookup, (triplet >> 12) & 63)
 			+ $charAt(lookup, (triplet >> 6) & 63)
-			+ '=';
+			+ (omitPadding ? '' : '=');
 	} else if (i + 1 === O.length) {
 		triplet = O[i] << 16;
 		result += $charAt(lookup, (triplet >> 18) & 63)
 			+ $charAt(lookup, (triplet >> 12) & 63)
-			+ '==';
+			+ (omitPadding ? '' : '==');
 	}
 	return result;
 };

test/Uint8Array.prototype.toBase64.js

@@ -228,10 +228,14 @@ module.exports = {
 			// standard test vectors from https://datatracker.ietf.org/doc/html/rfc4648#section-10
 			st.equal(method(new Uint8Array([])), '');
 			st.equal(method(new Uint8Array([102])), 'Zg==');
+			st.equal(method(new Uint8Array([102]), { omitPadding: true }), 'Zg');
 			st.equal(method(new Uint8Array([102, 111])), 'Zm8=');
+			st.equal(method(new Uint8Array([102, 111]), { omitPadding: true }), 'Zm8');
 			st.equal(method(new Uint8Array([102, 111, 111])), 'Zm9v');
 			st.equal(method(new Uint8Array([102, 111, 111, 98])), 'Zm9vYg==');
+			st.equal(method(new Uint8Array([102, 111, 111, 98]), { omitPadding: true }), 'Zm9vYg');
 			st.equal(method(new Uint8Array([102, 111, 111, 98, 97])), 'Zm9vYmE=');
+			st.equal(method(new Uint8Array([102, 111, 111, 98, 97]), { omitPadding: true }), 'Zm9vYmE');
 			st.equal(method(new Uint8Array([102, 111, 111, 98, 97, 114])), 'Zm9vYmFy');
 
 			st.end();