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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;
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