add anchor link scripts

1 files changed, 336 insertions, 0 deletions

diff --git a/assets/js/anchor.js b/assets/js/anchor.js
new file mode 100644
index 0000000..a73dc91
--- /dev/null
+++ b/assets/js/anchor.js
@@ -0,0 +1,336 @@
+/* eslint-env amd, node */
+
+// https://github.com/umdjs/umd/blob/master/templates/returnExports.js
+(function (root, factory) {
+  'use strict';
+
+  if (typeof define === 'function' && define.amd) {
+    // AMD. Register as an anonymous module.
+    define([], factory);
+  } else if (typeof module === 'object' && module.exports) {
+    // Node. Does not work with strict CommonJS, but
+    // only CommonJS-like environments that support module.exports,
+    // like Node.
+    module.exports = factory();
+  } else {
+    // Browser globals (root is window)
+    root.AnchorJS = factory();
+    root.anchors = new root.AnchorJS();
+  }
+}(this, function () {
+  'use strict';
+
+  function AnchorJS(options) {
+    this.options = options || {};
+    this.elements = [];
+
+    /**
+     * Assigns options to the internal options object, and provides defaults.
+     * @param {Object} opts - Options object
+     */
+    function _applyRemainingDefaultOptions(opts) {
+      opts.icon = opts.hasOwnProperty('icon') ? opts.icon : '\ue9cb'; // Accepts characters (and also URLs?), like  '#', '¶', '❡', or '§'.
+      opts.visible = opts.hasOwnProperty('visible') ? opts.visible : 'hover'; // Also accepts 'always' & 'touch'
+      opts.placement = opts.hasOwnProperty('placement') ? opts.placement : 'right'; // Also accepts 'left'
+      opts.ariaLabel = opts.hasOwnProperty('ariaLabel') ? opts.ariaLabel : 'Anchor'; // Accepts any text.
+      opts.class = opts.hasOwnProperty('class') ? opts.class : ''; // Accepts any class name.
+      // Using Math.floor here will ensure the value is Number-cast and an integer.
+      opts.truncate = opts.hasOwnProperty('truncate') ? Math.floor(opts.truncate) : 64; // Accepts any value that can be typecast to a number.
+    }
+
+    _applyRemainingDefaultOptions(this.options);
+
+    /**
+     * Checks to see if this device supports touch. Uses criteria pulled from Modernizr:
+     * https://github.com/Modernizr/Modernizr/blob/da22eb27631fc4957f67607fe6042e85c0a84656/feature-detects/touchevents.js#L40
+     * @return {Boolean} - true if the current device supports touch.
+     */
+    this.isTouchDevice = function() {
+      return !!(('ontouchstart' in window) || window.DocumentTouch && document instanceof DocumentTouch);
+    };
+
+    /**
+     * Add anchor links to page elements.
+     * @param  {String|Array|Nodelist} selector - A CSS selector for targeting the elements you wish to add anchor links
+     *                                            to. Also accepts an array or nodeList containing the relavant elements.
+     * @return {this}                           - The AnchorJS object
+     */
+    this.add = function(selector) {
+      var elements,
+          elsWithIds,
+          idList,
+          elementID,
+          i,
+          index,
+          count,
+          tidyText,
+          newTidyText,
+          readableID,
+          anchor,
+          visibleOptionToUse,
+          indexesToDrop = [];
+
+      // We reapply options here because somebody may have overwritten the default options object when setting options.
+      // For example, this overwrites all options but visible:
+      //
+      // anchors.options = { visible: 'always'; }
+      _applyRemainingDefaultOptions(this.options);
+
+      visibleOptionToUse = this.options.visible;
+      if (visibleOptionToUse === 'touch') {
+        visibleOptionToUse = this.isTouchDevice() ? 'always' : 'hover';
+      }
+
+      // Provide a sensible default selector, if none is given.
+      if (!selector) {
+        selector = 'h2, h3, h4, h5, h6';
+      }
+
+      elements = _getElements(selector);
+
+      if (elements.length === 0) {
+        return this;
+      }
+
+      _addBaselineStyles();
+
+      // We produce a list of existing IDs so we don't generate a duplicate.
+      elsWithIds = document.querySelectorAll('[id]');
+      idList = [].map.call(elsWithIds, function assign(el) {
+        return el.id;
+      });
+
+      for (i = 0; i < elements.length; i++) {
+        if (this.hasAnchorJSLink(elements[i])) {
+          indexesToDrop.push(i);
+          continue;
+        }
+
+        if (elements[i].hasAttribute('id')) {
+          elementID = elements[i].getAttribute('id');
+        } else if (elements[i].hasAttribute('data-anchor-id')) {
+          elementID = elements[i].getAttribute('data-anchor-id');
+        } else {
+          tidyText = this.urlify(elements[i].textContent);
+
+          // Compare our generated ID to existing IDs (and increment it if needed)
+          // before we add it to the page.
+          newTidyText = tidyText;
+          count = 0;
+          do {
+            if (index !== undefined) {
+              newTidyText = tidyText + '-' + count;
+            }
+
+            index = idList.indexOf(newTidyText);
+            count += 1;
+          } while (index !== -1);
+          index = undefined;
+          idList.push(newTidyText);
+
+          elements[i].setAttribute('id', newTidyText);
+          elementID = newTidyText;
+        }
+
+        readableID = elementID.replace(/-/g, ' ');
+
+        // The following code builds the following DOM structure in a more effiecient (albeit opaque) way.
+        // '<a class="anchorjs-link ' + this.options.class + '" href="#' + elementID + '" aria-label="Anchor" data-anchorjs-icon="' + this.options.icon + '"></a>';
+        anchor = document.createElement('a');
+        anchor.className = 'anchorjs-link ' + this.options.class;
+        anchor.href = '#' + elementID;
+        anchor.setAttribute('aria-label', this.options.ariaLabel);
+        anchor.setAttribute('data-anchorjs-icon', this.options.icon);
+
+        if (visibleOptionToUse === 'always') {
+          anchor.style.opacity = '1';
+        }
+
+        if (this.options.icon === '\ue9cb') {
+          anchor.style.font = '1em/1 anchorjs-icons';
+
+          // We set lineHeight = 1 here because the `anchorjs-icons` font family could otherwise affect the
+          // height of the heading. This isn't the case for icons with `placement: left`, so we restore
+          // line-height: inherit in that case, ensuring they remain positioned correctly. For more info,
+          // see https://github.com/bryanbraun/anchorjs/issues/39.
+          if (this.options.placement === 'left') {
+            anchor.style.lineHeight = 'inherit';
+          }
+        }
+
+        if (this.options.placement === 'left') {
+          anchor.style.position = 'absolute';
+          anchor.style.marginLeft = '-1em';
+          anchor.style.paddingRight = '0.5em';
+          elements[i].insertBefore(anchor, elements[i].firstChild);
+        } else { // if the option provided is `right` (or anything else).
+          anchor.style.paddingLeft = '0.375em';
+          elements[i].appendChild(anchor);
+        }
+      }
+
+      for (i = 0; i < indexesToDrop.length; i++) {
+        elements.splice(indexesToDrop[i] - i, 1);
+      }
+      this.elements = this.elements.concat(elements);
+
+      return this;
+    };
+
+    /**
+     * Removes all anchorjs-links from elements targed by the selector.
+     * @param  {String|Array|Nodelist} selector - A CSS selector string targeting elements with anchor links,
+     *                                            OR a nodeList / array containing the DOM elements.
+     * @return {this}                           - The AnchorJS object
+     */
+    this.remove = function(selector) {
+      var index,
+          domAnchor,
+          elements = _getElements(selector);
+
+      for (var i = 0; i < elements.length; i++) {
+        domAnchor = elements[i].querySelector('.anchorjs-link');
+        if (domAnchor) {
+          // Drop the element from our main list, if it's in there.
+          index = this.elements.indexOf(elements[i]);
+          if (index !== -1) {
+            this.elements.splice(index, 1);
+          }
+          // Remove the anchor from the DOM.
+          elements[i].removeChild(domAnchor);
+        }
+      }
+      return this;
+    };
+
+    /**
+     * Removes all anchorjs links. Mostly used for tests.
+     */
+    this.removeAll = function() {
+      this.remove(this.elements);
+    };
+
+    /**
+     * Urlify - Refine text so it makes a good ID.
+     *
+     * To do this, we remove apostrophes, replace nonsafe characters with hyphens,
+     * remove extra hyphens, truncate, trim hyphens, and make lowercase.
+     *
+     * @param  {String} text - Any text. Usually pulled from the webpage element we are linking to.
+     * @return {String}      - hyphen-delimited text for use in IDs and URLs.
+     */
+    this.urlify = function(text) {
+      // Regex for finding the nonsafe URL characters (many need escaping): & +$,:;=?@"#{}|^~[`%!'<>]./()*\
+      var nonsafeChars = /[& +$,:;=?@"#{}|^~[`%!'<>\]\.\/\(\)\*\\]/g,
+          urlText;
+
+      // The reason we include this _applyRemainingDefaultOptions is so urlify can be called independently,
+      // even after setting options. This can be useful for tests or other applications.
+      if (!this.options.truncate) {
+        _applyRemainingDefaultOptions(this.options);
+      }
+
+      // Note: we trim hyphens after truncating because truncating can cause dangling hyphens.
+      // Example string:                      // " ⚡⚡ Don't forget: URL fragments should be i18n-friendly, hyphenated, short, and clean."
+      urlText = text.trim()                   // "⚡⚡ Don't forget: URL fragments should be i18n-friendly, hyphenated, short, and clean."
+        .replace(/\'/gi, '')                  // "⚡⚡ Dont forget: URL fragments should be i18n-friendly, hyphenated, short, and clean."
+        .replace(nonsafeChars, '-')           // "⚡⚡-Dont-forget--URL-fragments-should-be-i18n-friendly--hyphenated--short--and-clean-"
+        .replace(/-{2,}/g, '-')               // "⚡⚡-Dont-forget-URL-fragments-should-be-i18n-friendly-hyphenated-short-and-clean-"
+        .substring(0, this.options.truncate)  // "⚡⚡-Dont-forget-URL-fragments-should-be-i18n-friendly-hyphenated-"
+        .replace(/^-+|-+$/gm, '')             // "⚡⚡-Dont-forget-URL-fragments-should-be-i18n-friendly-hyphenated"
+        .toLowerCase();                       // "⚡⚡-dont-forget-url-fragments-should-be-i18n-friendly-hyphenated"
+
+      return urlText;
+    };
+
+    /**
+     * Determines if this element already has an AnchorJS link on it.
+     * Uses this technique: http://stackoverflow.com/a/5898748/1154642
+     * @param    {HTMLElemnt}  el - a DOM node
+     * @return   {Boolean}     true/false
+     */
+    this.hasAnchorJSLink = function(el) {
+      var hasLeftAnchor = el.firstChild && ((' ' + el.firstChild.className + ' ').indexOf(' anchorjs-link ') > -1),
+          hasRightAnchor = el.lastChild && ((' ' + el.lastChild.className + ' ').indexOf(' anchorjs-link ') > -1),
+	  hasHSAnchor =  el.firstChild && ((' ' + el.firstChild.className + ' ').indexOf(' hideshow ') > -1);
+
+      return hasLeftAnchor || hasRightAnchor || hasHSAnchor || false;
+    };
+
+    /**
+     * Turns a selector, nodeList, or array of elements into an array of elements (so we can use array methods).
+     * It also throws errors on any other inputs. Used to handle inputs to .add and .remove.
+     * @param  {String|Array|Nodelist} input - A CSS selector string targeting elements with anchor links,
+     *                                         OR a nodeList / array containing the DOM elements.
+     * @return {Array} - An array containing the elements we want.
+     */
+    function _getElements(input) {
+      var elements;
+      if (typeof input === 'string' || input instanceof String) {
+        // See https://davidwalsh.name/nodelist-array for the technique transforming nodeList -> Array.
+        elements = [].slice.call(document.querySelectorAll(input));
+      // I checked the 'input instanceof NodeList' test in IE9 and modern browsers and it worked for me.
+      } else if (Array.isArray(input) || input instanceof NodeList) {
+        elements = [].slice.call(input);
+      } else {
+        throw new Error('The selector provided to AnchorJS was invalid.');
+      }
+      return elements.reverse();
+    }
+
+    /**
+     * _addBaselineStyles
+     * Adds baseline styles to the page, used by all AnchorJS links irregardless of configuration.
+     */
+    function _addBaselineStyles() {
+      // We don't want to add global baseline styles if they've been added before.
+      if (document.head.querySelector('style.anchorjs') !== null) {
+        return;
+      }
+
+      var style = document.createElement('style'),
+          linkRule =
+          ' .anchorjs-link {'                       +
+          '   opacity: 0;'                          +
+          '   text-decoration: none;'               +
+          '   -webkit-font-smoothing: antialiased;' +
+          '   -moz-osx-font-smoothing: grayscale;'  +
+          ' }',
+          hoverRule =
+          ' *:hover > .anchorjs-link,'              +
+          ' .anchorjs-link:focus  {'                +
+          '   opacity: 1;'                          +
+          ' }',
+          anchorjsLinkFontFace =
+          ' @font-face {'                           +
+          '   font-family: "anchorjs-icons";'       + // Icon from icomoon; 10px wide & 10px tall; 2 empty below & 4 above
+          '   src: url(data:n/a;base64,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) format("truetype");' +
+          ' }',
+          pseudoElContent =
+          ' [data-anchorjs-icon]::after {'          +
+          '   content: attr(data-anchorjs-icon);'   +
+          ' }',
+          firstStyleEl;
+
+      style.className = 'anchorjs';
+      style.appendChild(document.createTextNode('')); // Necessary for Webkit.
+
+      // We place it in the head with the other style tags, if possible, so as to
+      // not look out of place. We insert before the others so these styles can be
+      // overridden if necessary.
+      firstStyleEl = document.head.querySelector('[rel="stylesheet"], style');
+      if (firstStyleEl === undefined) {
+        document.head.appendChild(style);
+      } else {
+        document.head.insertBefore(style, firstStyleEl);
+      }
+
+      style.sheet.insertRule(linkRule, style.sheet.cssRules.length);
+      style.sheet.insertRule(hoverRule, style.sheet.cssRules.length);
+      style.sheet.insertRule(pseudoElContent, style.sheet.cssRules.length);
+      style.sheet.insertRule(anchorjsLinkFontFace, style.sheet.cssRules.length);
+    }
+  }
+
+  return AnchorJS;
+}));