Fixing assignment of base and returning original behavior, fixing base2 tests

Author: avoidwork

lib/filesize.es6.js

@@ -36,15 +36,24 @@
 	 * @param  {Object}  descriptor [Optional] Flags
 	 * @return {String}             Readable file size String
 	 */
-	function filesize (arg, {bits = false, pad = false, base = 10, round = 2, locale = "", localeOptions = {}, separator = "", spacer = " ", symbols = {}, standard = "iec", output = "string", fullform = false, fullforms = [], exponent = -1, roundingMethod = "round", precision = 0} = {}) {
+	function filesize (arg, {bits = false, pad = false, base = -1, round = 2, locale = "", localeOptions = {}, separator = "", spacer = " ", symbols = {}, standard = "", output = "string", fullform = false, fullforms = [], exponent = -1, roundingMethod = "round", precision = 0} = {}) {
 		let e = exponent,
 			num = Number(arg),
 			result = [],
 			val = 0,
 			u = "";
 
 		// Sync base & standard
-		base = standard === "iec" ? 10 : 2;
+		if (base === -1 && standard.length === 0) {
+			base = 10;
+			standard = "iec";
+		} else if (base === -1 && standard.length > 0) {
+			standard = standard === "iec" ? "iec" : "jedec";
+			base = standard === "iec" ? 10 : 2;
+		} else {
+			base = base === 2 ? 2 : 10;
+			standard = base === 10 ? "iec" : "jedec";
+		}
 
 		const ceil = base === 10 ? 1000 : 1024,
 			full = fullform === true,