Carlos Florêncio
65 lines
1.7 KiB
TypeScript
65 lines
1.7 KiB
TypeScript
type RehypeNode = {
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type: string;
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tagName?: string;
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properties?: Record<string, unknown>;
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children?: RehypeNode[];
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position?: RehypePosition;
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};
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type RehypePosition = {
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start: { line: number; column: number; offset?: number };
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end: { line: number; column: number; offset?: number };
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indent?: number[];
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};
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const MATH_SOURCE_CLASS = "markdown-math-source";
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function hasClass(node: RehypeNode | undefined, className: string): boolean {
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const value = node?.properties?.className;
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if (Array.isArray(value)) return value.includes(className);
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if (typeof value === "string") return value.split(/\s+/u).includes(className);
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return false;
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}
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function isDisplayMathPre(node: RehypeNode): boolean {
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const code = node.children?.[0];
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return (
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node.tagName === "pre" &&
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node.children?.length === 1 &&
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code?.tagName === "code" &&
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(hasClass(code, "language-math") || hasClass(code, "math-display"))
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);
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}
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function wrapDisplayMath(node: RehypeNode, source: RehypeNode): RehypeNode {
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return {
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type: "element",
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tagName: "div",
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properties: { className: [MATH_SOURCE_CLASS] },
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children: [node],
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position: source.position,
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};
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}
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function visit(node: RehypeNode): void {
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if (!node.children) return;
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for (let index = 0; index < node.children.length; index += 1) {
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const child = node.children[index];
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if (isDisplayMathPre(child)) {
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node.children[index] = wrapDisplayMath(child, child);
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continue;
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}
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visit(child);
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}
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}
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/** Preserve display-math source positions before rehype-katex replaces `<pre>`. */
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export function rehypeMathSource() {
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return (tree: RehypeNode) => {
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visit(tree);
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};
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}
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export { MATH_SOURCE_CLASS };
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