MCP JSON Navigator

/** * Navigate inside a JSON object using dot-paths. * Examples: * data.items.3.name * data.items[2].value * data.items.[0].options[4] * * Return either an object or a value. */ export function explore(data: any, jsonpath: string = ""): any { if (!jsonpath || jsonpath.trim() === "") return data; const parts = jsonpath.split("."); let current = data; for (const segment of parts) { // Case: "[3]" const bracketIndex = segment.match(/^\[(\d+)\]$/); if (bracketIndex) { const idx = Number(bracketIndex[1]); if (!Array.isArray(current)) throw new Error(`Expected list before index ${idx}`); if (idx >= current.length) throw new Error(`Index ${idx} out of range`); current = current[idx]; continue; } // Case: "3" if (Array.isArray(current) && /^\d+$/.test(segment)) { const idx = Number(segment); if (idx >= current.length) throw new Error(`Index ${idx} out of range`); current = current[idx]; continue; } // Case: key[index] const match = segment.match(/^([^\[]+)(?:\[(\d+)\])?$/); if (match) { const key = match[1]; const idx = match[2] !== undefined ? Number(match[2]) : null; if (typeof current !== "object" || current === null) { throw new Error(`Expected object before key "${key}"`); } if (!(key in current)) throw new Error(`Key not found: ${key}`); current = current[key]; if (idx !== null) { if (!Array.isArray(current)) throw new Error(`Key "${key}" is not a list`); if (idx >= current.length) throw new Error(`Index ${idx} out of range in list "${key}"`); current = current[idx]; } continue; } throw new Error(`Invalid path segment: ${segment}`); } return current; }