concatenate strings

lib/single-file/base64.js

@@ -128,15 +128,15 @@ this.base64 = this.base64 || (() => {
 
 	function encodeChunk(uint8, start, end) {
 		let tmp;
-		const output = [];
+		let output = "";
 		for (let i = start; i < end; i += 3) {
 			tmp =
 				((uint8[i] << 16) & 0xFF0000) +
 				((uint8[i + 1] << 8) & 0xFF00) +
 				(uint8[i + 2] & 0xFF);
-			output.push(tripletToBase64(tmp));
+			output += tripletToBase64(tmp);
 		}
-		return output.join("");
+		return output;
 	}
 
 	function fromByteArray(uint8) {