import katex from '../katex.mjs'; /* eslint no-constant-condition:0 */ const findEndOfMath = function findEndOfMath(delimiter, text, startIndex) { // Adapted from // https://github.com/Khan/perseus/blob/master/src/perseus-markdown.jsx let index = startIndex; let braceLevel = 0; const delimLength = delimiter.length; while (index < text.length) { const 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; }; const splitAtDelimiters = function splitAtDelimiters(startData, leftDelim, rightDelim, display) { const finalData = []; for (let i = 0; i < startData.length; i++) { if (startData[i].type === "text") { const text = startData[i].data; let lookingForLeft = true; let currIndex = 0; let 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; }; /* eslint no-console:0 */ const splitWithDelimiters = function splitWithDelimiters(text, delimiters) { let data = [{ type: "text", data: text }]; for (let i = 0; i < delimiters.length; i++) { const delimiter = delimiters[i]; data = splitAtDelimiters(data, delimiter.left, delimiter.right, delimiter.display || false); } return data; }; /* Note: optionsCopy is mutated by this method. If it is ever exposed in the * API, we should copy it before mutating. */ const renderMathInText = function renderMathInText(text, optionsCopy) { const data = splitWithDelimiters(text, optionsCopy.delimiters); const fragment = document.createDocumentFragment(); for (let i = 0; i < data.length; i++) { if (data[i].type === "text") { fragment.appendChild(document.createTextNode(data[i].data)); } else { const span = document.createElement("span"); let math = data[i].data; // Override any display mode defined in the settings with that // defined by the text itself optionsCopy.displayMode = data[i].display; try { if (optionsCopy.preProcess) { math = optionsCopy.preProcess(math); } katex.render(math, span, optionsCopy); } catch (e) { if (!(e instanceof katex.ParseError)) { throw e; } optionsCopy.errorCallback("KaTeX auto-render: Failed to parse `" + data[i].data + "` with ", e); fragment.appendChild(document.createTextNode(data[i].rawData)); continue; } fragment.appendChild(span); } } return fragment; }; const renderElem = function renderElem(elem, optionsCopy) { for (let i = 0; i < elem.childNodes.length; i++) { const childNode = elem.childNodes[i]; if (childNode.nodeType === 3) { // Text node const frag = renderMathInText(childNode.textContent, optionsCopy); i += frag.childNodes.length - 1; elem.replaceChild(frag, childNode); } else if (childNode.nodeType === 1) { // Element node const className = ' ' + childNode.className + ' '; const shouldRender = optionsCopy.ignoredTags.indexOf(childNode.nodeName.toLowerCase()) === -1 && optionsCopy.ignoredClasses.every(x => className.indexOf(' ' + x + ' ') === -1); if (shouldRender) { renderElem(childNode, optionsCopy); } } // Otherwise, it's something else, and ignore it. } }; const renderMathInElement = function renderMathInElement(elem, options) { if (!elem) { throw new Error("No element provided to render"); } const optionsCopy = {}; // Object.assign(optionsCopy, option) for (const option in options) { if (options.hasOwnProperty(option)) { optionsCopy[option] = options[option]; } } // default options optionsCopy.delimiters = optionsCopy.delimiters || [{ left: "$$", right: "$$", display: true }, { left: "\\(", right: "\\)", display: false }, // LaTeX uses $…$, but it ruins the display of normal `$` in text: // {left: "$", right: "$", display: false}, // \[…\] must come last in this array. Otherwise, renderMathInElement // will search for \[ before it searches for $$ or \( // That makes it susceptible to finding a \\[0.3em] row delimiter and // treating it as if it were the start of a KaTeX math zone. { left: "\\[", right: "\\]", display: true }]; optionsCopy.ignoredTags = optionsCopy.ignoredTags || ["script", "noscript", "style", "textarea", "pre", "code"]; optionsCopy.ignoredClasses = optionsCopy.ignoredClasses || []; optionsCopy.errorCallback = optionsCopy.errorCallback || console.error; // Enable sharing of global macros defined via `\gdef` between different // math elements within a single call to `renderMathInElement`. optionsCopy.macros = optionsCopy.macros || {}; renderElem(elem, optionsCopy); }; export default renderMathInElement;