fix: do not crash on unresolved domain (#22)

package.json

@@ -37,13 +37,15 @@
     "@types/mocha": "^5.2.5",
     "@types/nock": "^9.3.1",
     "@types/node": "^11.9.3",
+    "@types/sinon": "^7.0.5",
     "@types/update-notifier": "^2.5.0",
     "codecov": "^3.1.0",
     "gts": "^0.9.0",
     "mocha": "^5.0.0",
     "nock": "^10.0.6",
     "nyc": "^13.2.0",
     "semantic-release": "^15.13.3",
+    "sinon": "^7.2.3",
     "source-map-support": "^0.5.10",
     "typescript": "^3.3.3"
   },

src/index.ts

@@ -113,25 +113,32 @@ export class LinkChecker extends EventEmitter {
     }
 
     // Perform a HEAD or GET request based on the need to crawl
-    const res = await gaxios.request<string>({
-      method: 'GET',
-      url: opts.url,
-      responseType: opts.crawl ? 'text' : 'stream',
-      validateStatus: () => true
-    });
-    const result: LinkResult = {
-      url: opts.url,
-      status: res.status,
-      state: (res.status >= 200 && res.status < 300) ? LinkState.OK :
-                                                       LinkState.BROKEN
-    };
+    let status = 0;
+    let state = LinkState.BROKEN;
+    let data = '';
+    try {
+      const res = await gaxios.request<string>({
+        method: 'GET',
+        url: opts.url,
+        responseType: opts.crawl ? 'text' : 'stream',
+        validateStatus: () => true
+      });
+      status = res.status;
+      if (res.status >= 200 && res.status < 300) {
+        state = LinkState.OK;
+      }
+      data = res.data;
+    } catch (err) {
+      // request failure: invalid domain name, etc.
+    }
+    const result: LinkResult = {url: opts.url, status, state};
     opts.results.push(result);
     this.emit('link', result);
 
     // If we need to go deeper, scan the next level of depth for links and crawl
     if (opts.crawl) {
       this.emit('pagestart', opts.url);
-      const urls = getLinks(res.data, opts.checkOptions.path);
+      const urls = getLinks(data, opts.checkOptions.path);
       for (const url of urls) {
         // only crawl links that start with the same host
         const crawl = url.startsWith(opts.checkOptions.path);

test/test.ts

@@ -1,5 +1,8 @@
 import * as assert from 'assert';
+import * as gaxios from 'gaxios';
 import * as nock from 'nock';
+import * as sinon from 'sinon';
+
 import {check, LinkState} from '../src';
 
 nock.disableNetConnect();
@@ -48,6 +51,16 @@ describe('linkinator', () => {
     assert.strictEqual(results.links.length, 2);
   });
 
+  it('should handle fetch exceptions', async () => {
+    const requestStub = sinon.stub(gaxios, 'request');
+    requestStub.throws('Fetch error');
+    const results = await check({path: 'test/fixtures/basic'});
+    assert.ok(!results.passed);
+    assert.strictEqual(
+        results.links.filter(x => x.state === LinkState.BROKEN).length, 1);
+    requestStub.restore();
+  });
+
   it('should skip mailto: links', async () => {
     const results = await check({path: 'test/fixtures/mailto'});
     assert.ok(results.passed);