<script type="text/javascript"> /* global katex */ var findEndOfMath = function(delimiter, text, startIndex) { // Adapted from // https://github.com/Khan/perseus/blob/master/src/perseus-markdown.jsx var index = startIndex; var braceLevel = 0; var delimLength = delimiter.length; while (index < text.length) { var character = text[index]; if (braceLevel <= 0 && text.slice(index, index + delimLength) === delimiter) { return index; } else if (character === "\\") { index++; } else if (character === "{") { braceLevel++; } else if (character === "}") { braceLevel--; } index++; } return -1; }; var splitAtDelimiters = function(startData, leftDelim, rightDelim, display) { var finalData = []; for (var i = 0; i < startData.length; i++) { if (startData[i].type === "text") { var text = startData[i].data; var lookingForLeft = true; var currIndex = 0; var nextIndex; nextIndex = text.indexOf(leftDelim); if (nextIndex !== -1) { currIndex = nextIndex; finalData.push({ type: "text", data: text.slice(0, currIndex) }); lookingForLeft = false; } while (true) { if (lookingForLeft) { nextIndex = text.indexOf(leftDelim, currIndex); if (nextIndex === -1) { break; } finalData.push({ type: "text", data: text.slice(currIndex, nextIndex) }); currIndex = nextIndex; } else { nextIndex = findEndOfMath( rightDelim, text, currIndex + leftDelim.length); if (nextIndex === -1) { break; } finalData.push({ type: "math", data: text.slice( currIndex + leftDelim.length, nextIndex), rawData: text.slice( currIndex, nextIndex + rightDelim.length), display: display }); currIndex = nextIndex + rightDelim.length; } lookingForLeft = !lookingForLeft; } finalData.push({ type: "text", data: text.slice(currIndex) }); } else { finalData.push(startData[i]); } } return finalData; }; var splitWithDelimiters = function(text, delimiters) { var data = [{type: "text", data: text}]; for (var i = 0; i < delimiters.length; i++) { var delimiter = delimiters[i]; data = splitAtDelimiters( data, delimiter.left, delimiter.right, delimiter.display || false); } return data; }; var renderMathInText = function(text, delimiters) { var data = splitWithDelimiters(text, delimiters); var fragment = document.createDocumentFragment(); for (var i = 0; i < data.length; i++) { if (data[i].type === "text") { fragment.appendChild(document.createTextNode(data[i].data)); } else { var span = document.createElement("span"); var math = data[i].data; try { katex.render(math, span, { displayMode: data[i].display }); } catch (e) { if (!(e instanceof katex.ParseError)) { throw e; } console.error( "KaTeX auto-render: Failed to parse `" + data[i].data + "` with ", e ); fragment.appendChild(document.createTextNode(data[i].rawData)); continue; } fragment.appendChild(span); } } return fragment; }; var renderElem = function(elem, delimiters, ignoredTags) { for (var i = 0; i < elem.childNodes.length; i++) { var childNode = elem.childNodes[i]; if (childNode.nodeType === 3) { // Text node var frag = renderMathInText(childNode.textContent, delimiters); i += frag.childNodes.length - 1; elem.replaceChild(frag, childNode); } else if (childNode.nodeType === 1) { // Element node var shouldRender = ignoredTags.indexOf( childNode.nodeName.toLowerCase()) === -1; if (shouldRender) { renderElem(childNode, delimiters, ignoredTags); } } // Otherwise, it's something else, and ignore it. } }; var defaultOptions = { delimiters: [ {left: "$$", right: "$$", display: true}, {left: "\\[", right: "\\]", display: true}, {left: "\\(", right: "\\)", display: false} // LaTeX uses this, but it ruins the display of normal `$` in text: // {left: "$", right: "$", display: false} ], ignoredTags: [ "script", "noscript", "style", "textarea", "pre", "code" ] }; var extend = function(obj) { // Adapted from underscore.js' `_.extend`. See LICENSE.txt for license. var source, prop; for (var i = 1, length = arguments.length; i < length; i++) { source = arguments[i]; for (prop in source) { if (Object.prototype.hasOwnProperty.call(source, prop)) { obj[prop] = source[prop]; } } } return obj; }; var renderMathInElement = function(elem, options) { if (!elem) { throw new Error("No element provided to render"); } options = extend({}, defaultOptions, options); renderElem(elem, options.delimiters, options.ignoredTags); }; renderMathInElement(document.body); </script>