fix: Fix thrown error with input that only contains whitespaces

Fix issues #32, #61

Author: jpstevens

src/parseDomain.js

@@ -56,7 +56,7 @@ function parseDomain(url, options) {
     let urlSplit;
     let domain;
 
-    if (normalizedUrl === null) {
+    if (!normalizedUrl) {
         return null;
     }
 

test/parseDomain.test.js

@@ -142,6 +142,8 @@ describe("parseDomain(url)", () => {
         expect(parseDomain(undefined)).to.equal(null);
         expect(parseDomain({})).to.equal(null);
         expect(parseDomain("")).to.equal(null);
+        expect(parseDomain(" ")).to.equal(null);
+        expect(parseDomain("\xa0")).to.equal(null);
     });
 
     it("should work with domains that could match multiple tlds", () => {