improve #linkPrev and #linkNext:

- add support for <link> elements
- match if there's more than one rel e.g. <a rel="nofollow next">...</a>
- more tests

src/content/navigates.js

@@ -2,13 +2,14 @@ const PREV_LINK_PATTERNS = [
   /\bprev\b/i, /\bprevious\b/i, /\bback\b/i,
   /</, /\u2039/, /\u2190/, /\xab/, /\u226a/, /<</
 ];
+
 const NEXT_LINK_PATTERNS = [
   /\bnext\b/i,
   />/, /\u203a/, /\u2192/, /\xbb/, /\u226b/, />>/
 ];
 
 const findLinkByPatterns = (win, patterns) => {
-  let links = win.document.getElementsByTagName('a');
+  const links = win.document.getElementsByTagName('a');
   return Array.prototype.find.call(links, (link) => {
     return patterns.some(ptn => ptn.test(link.textContent));
   });
@@ -22,30 +23,32 @@ const historyNext = (win) => {
   win.history.forward();
 };
 
-const linkPrev = (win) => {
+const linkCommon = (win, rel, patterns) => {
-  let link = win.document.querySelector('a[rel=prev]');
+  let link = win.document.querySelector(`link[rel~=${rel}][href]`);
+
   if (link) {
-    return link.click();
+    win.location = link.getAttribute('href');
+    return;
   }
-  link = findLinkByPatterns(win, PREV_LINK_PATTERNS);
+
+  link = win.document.querySelector(`a[rel~=${rel}]`) ||
+    findLinkByPatterns(win, patterns);
+
   if (link) {
     link.click();
   }
 };
 
+const linkPrev = (win) => {
+  linkCommon(win, 'prev', PREV_LINK_PATTERNS);
+};
+
 const linkNext = (win) => {
-  let link = win.document.querySelector('a[rel=next]');
+  linkCommon(win, 'next', NEXT_LINK_PATTERNS);
-  if (link) {
-    return link.click();
-  }
-  link = findLinkByPatterns(win, NEXT_LINK_PATTERNS);
-  if (link) {
-    link.click();
-  }
 };
 
 const parent = (win) => {
-  let loc = win.location;
+  const loc = win.location;
   if (loc.hash !== '') {
     loc.hash = '';
     return;

test/content/navigates.test.js

@@ -1,56 +1,138 @@
-import { expect } from "chai";
+import { expect } from 'chai';
 import * as navigates from 'content/navigates';
 
-describe('navigates module', () => {
+const testRel = (done, rel, html) => {
-  describe('#linkPrev', () => {
+  const method = rel === 'prev' ? 'linkPrev' : 'linkNext';
-    it('clicks prev link by text content', (done) => {
+  document.body.innerHTML = html;
-      document.body.innerHTML = '<a href="#dummy">xprevx</a>  <a href="#prev">go to prev</a>';
+  navigates[method](window);
-      navigates.linkPrev(window);
   setTimeout(() => {
-        expect(document.location.hash).to.equal('#prev');
+    expect(document.location.hash).to.equal(`#${rel}`);
     done();
   }, 0);
-    });
+};
 
-    it('clicks a[rel=prev] element preferentially', (done) => {
+const testPrev = html => done => testRel(done, 'prev', html);
-      document.body.innerHTML = '<a href="#dummy">prev</a>  <a rel="prev" href="#prev">rel</a>';
+const testNext = html => done => testRel(done, 'next', html);
-      navigates.linkPrev(window);
-      setTimeout(() => {
-        expect(document.location.hash).to.equal('#prev');
-        done();
-      }, 0);
-    });
-  });
 
+describe('navigates module', () => {
+  describe('#linkPrev', () => {
+    it('navigates to <link> elements whose rel attribute is "prev"', testPrev(
+      '<link rel="prev" href="#prev" />'
+    ));
 
-  describe('#linkNext', () => {
+    it('navigates to <link> elements whose rel attribute starts with "prev"', testPrev(
-    it('clicks next link by text content', (done) => {
+      '<link rel="prev bar" href="#prev" />'
-      document.body.innerHTML = '<a href="#dummy">xnextx</a>  <a href="#next">go to next</a>';
+    ));
-      navigates.linkNext(window);
-      setTimeout(() => {
-        expect(document.location.hash).to.equal('#next');
-        done();
-      }, 0);
-    });
 
-    it('clicks a[rel=next] element preferentially', (done) => {
+    it('navigates to <link> elements whose rel attribute ends with "prev"', testPrev(
-      document.body.innerHTML = '<a href="#dummy">next</a>  <a rel="next" href="#next">rel</a>';
+      '<link rel="foo prev" href="#prev" />'
-      navigates.linkNext(window);
+    ));
-      setTimeout(() => {
+
-        expect(document.location.hash).to.equal('#next');
+    it('navigates to <link> elements whose rel attribute contains "prev"', testPrev(
-        done();
+      '<link rel="foo prev bar" href="#prev" />'
-      }, 0);
+    ));
+
+    it('navigates to <a> elements whose rel attribute is "prev"', testPrev(
+      '<a rel="prev" href="#prev">click me</a>'
+    ));
+
+    it('navigates to <a> elements whose rel attribute starts with "prev"', testPrev(
+      '<a rel="prev bar" href="#prev">click me</a>'
+    ));
+
+    it('navigates to <a> elements whose rel attribute ends with "prev"', testPrev(
+      '<a rel="foo prev" href="#prev">click me</a>'
+    ));
+
+    it('navigates to <a> elements whose rel attribute contains "prev"', testPrev(
+      '<a rel="foo prev bar" href="#prev">click me</a>'
+    ));
+
+    it('navigates to <a> elements whose text matches "prev"', testPrev(
+      '<a href="#dummy">preview</a><a href="#prev">go to prev</a>'
+    ));
+
+    it('navigates to <a> elements whose text matches "previous"', testPrev(
+      '<a href="#dummy">preview</a><a href="#prev">go to previous</a>'
+    ));
+
+    it('navigates to <a> elements whose decoded text matches "<<"', testPrev(
+      '<a href="#dummy">click me</a><a href="#prev">&lt;&lt;</a>'
+    ));
+
+    it('navigates to matching <a> elements by clicking', testPrev(
+      `<a rel="prev" href="#dummy" onclick="return location = '#prev', false">go to prev</a>`
+    ));
+
+    it('prefers link[rel~=prev] to a[rel~=prev]', testPrev(
+      '<a rel="prev" href="#dummy">click me</a><link rel="prev" href="#prev" />'
+    ));
+
+    it('prefers a[rel~=prev] to a::text(pattern)', testPrev(
+      '<a href="#dummy">go to prev</a><a rel="prev" href="#prev">click me</a>'
+    ));
   });
+
+  describe('#linkNext', () => {
+    it('navigates to <link> elements whose rel attribute is "next"', testNext(
+      '<link rel="next" href="#next" />'
+    ));
+
+    it('navigates to <link> elements whose rel attribute starts with "next"', testNext(
+      '<link rel="next bar" href="#next" />'
+    ));
+
+    it('navigates to <link> elements whose rel attribute ends with "next"', testNext(
+      '<link rel="foo next" href="#next" />'
+    ));
+
+    it('navigates to <link> elements whose rel attribute contains "next"', testNext(
+      '<link rel="foo next bar" href="#next" />'
+    ));
+
+    it('navigates to <a> elements whose rel attribute is "next"', testNext(
+      '<a rel="next" href="#next">click me</a>'
+    ));
+
+    it('navigates to <a> elements whose rel attribute starts with "next"', testNext(
+      '<a rel="next bar" href="#next">click me</a>'
+    ));
+
+    it('navigates to <a> elements whose rel attribute ends with "next"', testNext(
+      '<a rel="foo next" href="#next">click me</a>'
+    ));
+
+    it('navigates to <a> elements whose rel attribute contains "next"', testNext(
+      '<a rel="foo next bar" href="#next">click me</a>'
+    ));
+
+    it('navigates to <a> elements whose text matches "next"', testNext(
+      '<a href="#dummy">inextricable</a><a href="#next">go to next</a>'
+    ));
+
+    it('navigates to <a> elements whose decoded text matches ">>"', testNext(
+      '<a href="#dummy">click me</a><a href="#next">&gt;&gt;</a>'
+    ));
+
+    it('navigates to matching <a> elements by clicking', testNext(
+      `<a rel="next" href="#dummy" onclick="return location = '#next', false">go to next</a>`
+    ));
+
+    it('prefers link[rel~=next] to a[rel~=next]', testNext(
+      '<a rel="next" href="#dummy">click me<><link rel="next" href="#next" />'
+    ));
+
+    it('prefers a[rel~=next] to a::text(pattern)', testNext(
+      '<a href="#dummy">go to next</a><a rel="next" href="#next">click me</a>'
+    ));
   });
 
   describe('#parent', () => {
     // NOTE: not able to test location
     it('removes hash', () => {
-      window.location.hash = "#section-1";
+      window.location.hash = '#section-1';
       navigates.parent(window);
       expect(document.location.hash).to.be.empty;
     });
   });
 });
-
-