86 lines
2.2 KiB
JavaScript
86 lines
2.2 KiB
JavaScript
|
/* eslint no-constant-condition:0 */
|
||
|
|
const findEndOfMath = function(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 escapeRegex = function(string) {
|
||
|
|
return string.replace(/[-/\\^$*+?.()|[\]{}]/g, "\\$&");
|
||
|
|
};
|
||
|
|
|
||
|
|
const amsRegex = /^\\begin{/;
|
||
|
|
|
||
|
|
const splitAtDelimiters = function(text, delimiters) {
|
||
|
|
let index;
|
||
|
|
const data = [];
|
||
|
|
|
||
|
|
const regexLeft = new RegExp(
|
||
|
|
"(" + delimiters.map((x) => escapeRegex(x.left)).join("|") + ")"
|
||
|
|
);
|
||
|
|
|
||
|
|
while (true) {
|
||
|
|
index = text.search(regexLeft);
|
||
|
|
if (index === -1) {
|
||
|
|
break;
|
||
|
|
}
|
||
|
|
if (index > 0) {
|
||
|
|
data.push({
|
||
|
|
type: "text",
|
||
|
|
data: text.slice(0, index),
|
||
|
|
});
|
||
|
|
text = text.slice(index); // now text starts with delimiter
|
||
|
|
}
|
||
|
|
// ... so this always succeeds:
|
||
|
|
const i = delimiters.findIndex((delim) => text.startsWith(delim.left));
|
||
|
|
index = findEndOfMath(delimiters[i].right, text, delimiters[i].left.length);
|
||
|
|
if (index === -1) {
|
||
|
|
break;
|
||
|
|
}
|
||
|
|
const rawData = text.slice(0, index + delimiters[i].right.length);
|
||
|
|
const math = amsRegex.test(rawData)
|
||
|
|
? rawData
|
||
|
|
: text.slice(delimiters[i].left.length, index);
|
||
|
|
data.push({
|
||
|
|
type: "math",
|
||
|
|
data: math,
|
||
|
|
rawData,
|
||
|
|
display: delimiters[i].display,
|
||
|
|
});
|
||
|
|
text = text.slice(index + delimiters[i].right.length);
|
||
|
|
}
|
||
|
|
|
||
|
|
if (text !== "") {
|
||
|
|
data.push({
|
||
|
|
type: "text",
|
||
|
|
data: text,
|
||
|
|
});
|
||
|
|
}
|
||
|
|
|
||
|
|
return data;
|
||
|
|
};
|
||
|
|
|
||
|
|
export default splitAtDelimiters;
|