Mermaid-Grammer-Inspector

/** * Mermaid syntax parser */ import { exec } from "node:child_process"; import path from "node:path"; import { fileURLToPath } from "node:url"; const __dirname = path.dirname(fileURLToPath(import.meta.url)); export enum ParseStatus { SUCCESS, FAIL, } export interface ParseResult { status: ParseStatus; message?: string; } /** * Filter redundant information from error output */ const filterErrorOutput = (errorOutput: string): string => { if (!errorOutput || typeof errorOutput !== "string") { return ""; } // Remove npm warnings const filtered = errorOutput.replace(/npm warn[^\n]*\n/gi, ""); const lines = filtered.split("\n"); const filteredLines: string[] = []; let foundError = false; for (const line of lines) { const trimmed = line.trim(); // Skip empty lines and npm warnings if (!trimmed || trimmed.toLowerCase().includes("npm warn")) continue; // Stop at stack trace lines if (trimmed.startsWith("at ") || trimmed.startsWith("at async")) break; // Capture error messages if (trimmed.startsWith("Error:") || foundError) { foundError = true; filteredLines.push(line); } } const result = filteredLines.length > 0 ? filteredLines.join("\n").trim() : errorOutput.trim(); return result || "Unknown parsing error"; }; /** * Parse Mermaid diagram syntax * @param inputFile Input file name * @param outputFile Output file name * @returns Parse result */ export const parseMermaid = ( inputFile: string = "input.mmd", outputFile: string = "output.svg", ): Promise<ParseResult> => { return new Promise((resolve) => { const inputPath = path.join(__dirname, inputFile); const outputPath = path.join(__dirname, outputFile); exec( `npx mmdc -i ${inputPath} -o ${outputPath}`, (err, _stdout, stderr) => { if (err) { const errorOutput = stderr || err.message || ""; const filteredMessage = filterErrorOutput(errorOutput); resolve({ status: ParseStatus.FAIL, message: filteredMessage || err.message || "Unknown error", }); return; } resolve({ status: ParseStatus.SUCCESS }); }, ); }); };