index.js

export const stringify = (json) => {
  let count = 0;
  let list = [];
  let str = JSON.stringify(json, function (key, val) {
    if (typeof val === 'function') {
      list.push(val + '');
      const result = '$code{' + count + '}$code'
      count = count + 1;
      return result
    }
    return val;
  }, 2);
  let startCode = '$code{';
  let endCode = '}$code';
  list.forEach((ele, index) => {
    str = str.replace(startCode + index + endCode, startCode + ele + endCode)
  })
  for (let i = 0; i < count; i++) {
    str = str.replace('"' + startCode, '').replace(endCode + '"', '')
  }
  return str
}