refactor(isExternal): avoid undefined & improve performance

lib/is_external_link.js

@@ -1,37 +1,34 @@
 'use strict';
 
-const { URL } = require('url');
-
-const urlObj = (str) => {
-  try {
-    return new URL(str);
-  } catch (err) {
-    return str;
-  }
-};
+const { parse, URL } = require('url');
 
 /**
  * Check whether the link is external
- * @param {String} url The url to check
+ * @param {String} input The url to check
  * @returns {Boolean} True if the link doesn't have protocol or link has same host with config.url
  */
 
-function isExternalLink(url) {
+function isExternalLink(input) {
   const { config } = this;
-  const exclude = Array.isArray(config.external_link.exclude) ? config.external_link.exclude
-    : [config.external_link.exclude];
-  const data = urlObj(url);
-  const host = data.hostname;
-  const sitehost = typeof urlObj(config.url) === 'object' ? urlObj(config.url).hostname : config.url;
+  const sitehost = parse(config.url).hostname || config.url;
+  if (!sitehost) return false;
 
-  if (!sitehost || typeof data === 'string') return false;
+  // handle relative url
+  const data = new URL(input, `http://${sitehost}`);
 
   // handle mailto: javascript: vbscript: and so on
   if (data.origin === 'null') return false;
 
-  if (exclude && exclude.length) {
-    for (const i of exclude) {
-      if (host === i) return false;
+  const host = data.hostname;
+
+  if (config.external_link && config.external_link.exclude) {
+    const exclude = Array.isArray(config.external_link.exclude) ? config.external_link.exclude
+      : [config.external_link.exclude];
+
+    if (exclude && exclude.length) {
+      for (const i of exclude) {
+        if (host === i) return false;
+      }
     }
   }
 

test/is_external_link.spec.js

@@ -3,8 +3,7 @@
 describe('isExternalLink', () => {
   const ctx = {
     config: {
-      url: 'https://example.com',
-      external_link: {}
+      url: 'https://example.com'
     }
   };
 
@@ -28,19 +27,25 @@ describe('isExternalLink', () => {
   });
 
   it('exclude - empty string', () => {
-    ctx.config.external_link.exclude = '';
+    ctx.config.external_link = {
+      exclude: ''
+    };
     isExternalLink('https://hexo.io/').should.eql(true);
   });
 
   it('exclude - string', () => {
-    ctx.config.external_link.exclude = 'foo.com';
+    ctx.config.external_link = {
+      exclude: 'foo.com'
+    };
     isExternalLink('https://foo.com/').should.eql(false);
     isExternalLink('https://bar.com/').should.eql(true);
     isExternalLink('https://baz.com/').should.eql(true);
   });
 
   it('exclude - array', () => {
-    ctx.config.external_link.exclude = ['foo.com', 'bar.com'];
+    ctx.config.external_link = {
+      exclude: ['foo.com', 'bar.com']
+    };
     isExternalLink('https://foo.com/').should.eql(false);
     isExternalLink('https://bar.com/').should.eql(false);
     isExternalLink('https://baz.com/').should.eql(true);