Intlayer

/** * Extracts and parses the first valid JSON value (object or array) from a string containing arbitrary text. * This is used to safely extract JSON from LLM responses that may contain additional text or markdown. * * @example * // Extracts JSON object from markdown response: * ```json * { * "title": "Test content declarations", * "description": "A comprehensive test dictionary...", * "tags": ["test tag"] * } * ``` * * @example * // Extracts JSON array: * ```json * ["item1", "item2", "item3"] * ``` * * @example * // Extracts JSON from markdown: * Here is the response: * ```json * {"key": "value"} * ``` * End of response. * * @throws {Error} If no valid JSON object/array is found or if parsing fails * @returns {T} The parsed JSON value cast to type T */ export const extractJson = <T = any>(input: string): T => { const opening = input.match(/[{[]/); if (!opening) throw new Error('No JSON start character ({ or [) found.'); const startIdx = opening.index!; const openChar = input[startIdx]; const closeChar = openChar === '{' ? '}' : ']'; let depth = 0; for (let i = startIdx; i < input.length; i++) { const char = input[i]; if (char === openChar) depth++; else if (char === closeChar) { depth--; if (depth === 0) { const jsonSubstring = input.slice(startIdx, i + 1); try { return JSON.parse(jsonSubstring) as T; } catch (err) { throw new Error(`Failed to parse JSON: ${(err as Error).message}`); } } } } throw new Error('Reached end of input without closing JSON bracket.'); };