const katex = require('katex') /* global WIKI */ // ------------------------------------ // Markdown - KaTeX Renderer // ------------------------------------ // // Includes code from https://github.com/liradb2000/markdown-it-katex module.exports = { init (mdinst, conf) { if (conf.useInline) { mdinst.inline.ruler.after('escape', 'katex_inline', katexInline) mdinst.renderer.rules.katex_inline = (tokens, idx) => { try { return katex.renderToString(tokens[idx].content, { displayMode: false }) } catch (err) { WIKI.logger.warn(err) return tokens[idx].content } } } if (conf.useBlocks) { mdinst.block.ruler.after('blockquote', 'katex_block', katexBlock, { alt: [ 'paragraph', 'reference', 'blockquote', 'list' ] }) mdinst.renderer.rules.katex_block = (tokens, idx) => { try { return `

` + katex.renderToString(tokens[idx].content, { displayMode: true }) + `

` } catch (err) { WIKI.logger.warn(err) return tokens[idx].content } } } } } // Test if potential opening or closing delimieter // Assumes that there is a "$" at state.src[pos] function isValidDelim (state, pos) { let prevChar let nextChar let max = state.posMax let canOpen = true let canClose = true prevChar = pos > 0 ? state.src.charCodeAt(pos - 1) : -1 nextChar = pos + 1 <= max ? state.src.charCodeAt(pos + 1) : -1 // Check non-whitespace conditions for opening and closing, and // check that closing delimeter isn't followed by a number if (prevChar === 0x20/* " " */ || prevChar === 0x09/* \t */ || (nextChar >= 0x30/* "0" */ && nextChar <= 0x39/* "9" */)) { canClose = false } if (nextChar === 0x20/* " " */ || nextChar === 0x09/* \t */) { canOpen = false } return { canOpen: canOpen, canClose: canClose } } function katexInline (state, silent) { let start, match, token, res, pos if (state.src[state.pos] !== '$') { return false } res = isValidDelim(state, state.pos) if (!res.canOpen) { if (!silent) { state.pending += '$' } state.pos += 1 return true } // First check for and bypass all properly escaped delimieters // This loop will assume that the first leading backtick can not // be the first character in state.src, which is known since // we have found an opening delimieter already. start = state.pos + 1 match = start while ((match = state.src.indexOf('$', match)) !== -1) { // Found potential $, look for escapes, pos will point to // first non escape when complete pos = match - 1 while (state.src[pos] === '\\') { pos -= 1 } // Even number of escapes, potential closing delimiter found if (((match - pos) % 2) === 1) { break } match += 1 } // No closing delimter found. Consume $ and continue. if (match === -1) { if (!silent) { state.pending += '$' } state.pos = start return true } // Check if we have empty content, ie: $$. Do not parse. if (match - start === 0) { if (!silent) { state.pending += '$$' } state.pos = start + 1 return true } // Check for valid closing delimiter res = isValidDelim(state, match) if (!res.canClose) { if (!silent) { state.pending += '$' } state.pos = start return true } if (!silent) { token = state.push('katex_inline', 'math', 0) token.markup = '$' token.content = state.src.slice(start, match) } state.pos = match + 1 return true } function katexBlock (state, start, end, silent) { let firstLine; let lastLine; let next; let lastPos; let found = false; let token let pos = state.bMarks[start] + state.tShift[start] let max = state.eMarks[start] if (pos + 2 > max) { return false } if (state.src.slice(pos, pos + 2) !== '$$') { return false } pos += 2 firstLine = state.src.slice(pos, max) if (silent) { return true } if (firstLine.trim().slice(-2) === '$$') { // Single line expression firstLine = firstLine.trim().slice(0, -2) found = true } for (next = start; !found;) { next++ if (next >= end) { break } pos = state.bMarks[next] + state.tShift[next] max = state.eMarks[next] if (pos < max && state.tShift[next] < state.blkIndent) { // non-empty line with negative indent should stop the list: break } if (state.src.slice(pos, max).trim().slice(-2) === '$$') { lastPos = state.src.slice(0, max).lastIndexOf('$$') lastLine = state.src.slice(pos, lastPos) found = true } } state.line = next + 1 token = state.push('katex_block', 'math', 0) token.block = true token.content = (firstLine && firstLine.trim() ? firstLine + '\n' : '') + state.getLines(start + 1, next, state.tShift[start], true) + (lastLine && lastLine.trim() ? lastLine : '') token.map = [ start, state.line ] token.markup = '$$' return true }