ensure-json/dist/index.js

A <3kB, dependency-free helper that repairs 'almost-JSON' text from LLMs and returns a valid JavaScript object—or throws JsonFixError.

// src/ensureJson.ts
var JsonFixError = class extends Error {
  constructor(msg, raw) {
    super(msg);
    this.name = "JsonFixError";
    this.raw = raw;
  }
};
function ensureJson(raw, schema) {
  let parsed;
  try {
    parsed = JSON.parse(raw);
  } catch {
    parsed = tryRepair(raw);
  }
  if (schema) {
    const result = schema.safeParse(parsed);
    if (!result.success) {
      throw new JsonFixError("Schema validation failed", raw);
    }
    return result.data;
  }
  return parsed;
}
async function ensureJsonAsync(raw, schema) {
  return ensureJson(raw, schema);
}
function tryRepair(raw) {
  let text = raw;
  text = text.replace(/^\s*```(?:json)?|```\s*$/gim, "");
  const firstBrace = Math.min(
    ...["{", "["].map((c) => {
      const i = text.indexOf(c);
      return i === -1 ? Infinity : i;
    })
  );
  if (firstBrace !== Infinity) text = text.slice(firstBrace);
  text = text.replace(/,\s*([}\]])/g, "$1");
  text = text.replace(/'([^']+)':/g, (_, k) => `"${k}":`);
  text = text.replace(/([{,]\s*)([a-zA-Z0-9_]+)\s*:/g, '$1"$2":');
  const openBraces = (text.match(/{/g) || []).length;
  const closeBraces = (text.match(/}/g) || []).length;
  if (openBraces === closeBraces + 1) text += "}";
  const openBrackets = (text.match(/\[/g) || []).length;
  const closeBrackets = (text.match(/]/g) || []).length;
  if (openBrackets === closeBrackets + 1) text += "]";
  try {
    return JSON.parse(text);
  } catch (err) {
    throw new JsonFixError("Failed to repair and parse JSON", raw);
  }
}
export {
  JsonFixError,
  ensureJson,
  ensureJsonAsync
};