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1// Set these to how you want inline and display math to be delimited.
2const defaultCopyDelimiters = {
3  inline: ['$', '$'],
4  // alternative: ['\(', '\)']
5  display: ['$$', '$$'] // alternative: ['\[', '\]']
6
7}; // Replace .katex elements with their TeX source (<annotation> element).
8// Modifies fragment in-place.  Useful for writing your own 'copy' handler,
9// as in copy-tex.js.
10
11const katexReplaceWithTex = function katexReplaceWithTex(fragment, copyDelimiters) {
12  if (copyDelimiters === void 0) {
13    copyDelimiters = defaultCopyDelimiters;
14  }
15
16  // Remove .katex-html blocks that are preceded by .katex-mathml blocks
17  // (which will get replaced below).
18  const katexHtml = fragment.querySelectorAll('.katex-mathml + .katex-html');
19
20  for (let i = 0; i < katexHtml.length; i++) {
21    const element = katexHtml[i];
22
23    if (element.remove) {
24      element.remove(null);
25    } else {
26      element.parentNode.removeChild(element);
27    }
28  } // Replace .katex-mathml elements with their annotation (TeX source)
29  // descendant, with inline delimiters.
30
31
32  const katexMathml = fragment.querySelectorAll('.katex-mathml');
33
34  for (let i = 0; i < katexMathml.length; i++) {
35    const element = katexMathml[i];
36    const texSource = element.querySelector('annotation');
37
38    if (texSource) {
39      if (element.replaceWith) {
40        element.replaceWith(texSource);
41      } else {
42        element.parentNode.replaceChild(texSource, element);
43      }
44
45      texSource.innerHTML = copyDelimiters.inline[0] + texSource.innerHTML + copyDelimiters.inline[1];
46    }
47  } // Switch display math to display delimiters.
48
49
50  const displays = fragment.querySelectorAll('.katex-display annotation');
51
52  for (let i = 0; i < displays.length; i++) {
53    const element = displays[i];
54    element.innerHTML = copyDelimiters.display[0] + element.innerHTML.substr(copyDelimiters.inline[0].length, element.innerHTML.length - copyDelimiters.inline[0].length - copyDelimiters.inline[1].length) + copyDelimiters.display[1];
55  }
56
57  return fragment;
58};
59
60document.addEventListener('copy', function (event) {
61  const selection = window.getSelection();
62
63  if (selection.isCollapsed) {
64    return; // default action OK if selection is empty
65  }
66
67  const fragment = selection.getRangeAt(0).cloneContents();
68
69  if (!fragment.querySelector('.katex-mathml')) {
70    return; // default action OK if no .katex-mathml elements
71  } // Preserve usual HTML copy/paste behavior.
72
73
74  const html = [];
75
76  for (let i = 0; i < fragment.childNodes.length; i++) {
77    html.push(fragment.childNodes[i].outerHTML);
78  }
79
80  event.clipboardData.setData('text/html', html.join('')); // Rewrite plain-text version.
81
82  event.clipboardData.setData('text/plain', katexReplaceWithTex(fragment).textContent); // Prevent normal copy handling.
83
84  event.preventDefault();
85});
86