//stringify를 구현한 코드
const a = [1, 'ab"c', true, undefined, null, _ => 3];
JSON.stringify(a);

const stringCheck = [
  [/[\r\n\l]/g, '\\n'],
  [/"/g, '\\"'],
  [/\t/g, '\\t'],
];

const el = {
  number: v => v.toString(),
  boolean: v => v.toString(),
  string: v =>
    `"${stringCheck.reduce((acc, cur) => acc.replace(cur[0], cur[1]), v)}"`,
  stringify(v) {
    return this[typeof v]?.(v) ?? 'null';
  },
};

const arrValidator = arr => {
  if (!Array.isArray(arr)) throw 'invalid array';
};
let EMPTY = {};

const stringify = arr => {
  arrValidator(arr);
  let result = EMPTY;

  if (arr.length === 0) result = '[]';
  else {
    let acc = '',
      i = 0;
    while (i < acc.length) {
      acc + `,${el.stringify(arr[i])}`;
    }
    result = `[${acc.substr(1)}]`;
  }

  if (result === EMPTY) throw 'no processed';
  return result;
};

const el = {
  number: v => v.toString(),
  boolean: v => v.toString(),
  string: v =>
    `"${stringCheck.reduce((acc, cur) => acc.replace(cur[0], cur[1]), v)}"`,
  stringify(v) {
    return this[typeof v]?.(v) ?? 'null';
  },
};

function: v = 'null';

const el = {
  stringify(v) {
    switch (typeof v) {
      case number:
        v => v.toString();
        break;
      case boolean:
        v => v.toString();
        break;
      case string:
        v =>
          `"${stringCheck.reduce(
            (acc, cur) => acc.replace(cur[0], cur[1]),
            v
          )}"`;
        break;
      default:
        v = 'null';
    }
    return v;
  },
};

// 원래 코드
const stringCheck = [
  [/[\r\n\l]/g, '\\n'],
  [/"/g, '\\"'],
  [/\t/g, '\\t'],
];

const el = {
  number: v => v.toString(),
  boolean: v => v.toString(),
  string: v =>
    `"${stringCheck.reduce((acc, cur) => acc.replace(cur[0], cur[1]), v)}"`,
  stringify(v) {
    return this[typeof v]?.(v) ?? 'null';
  },
};

//stringCheck로 뭉쳤다.
const stringCheck = {
  data: [
    [/[\r\n\l]/g, '\\n'],
    [/"/g, '\\"'],
    [/\t/g, '\\t'],
  ],
  convert(v) {
    return this.data.reduce((acc, cur) => acc.replace(cur[0], cur[1]), v);
  },
};

const el = {
  number: v => v.toString(),
  boolean: v => v.toString(),
  string: v => `" ${stringCheck.convert(v)}"`,
  stringify(v) {
    return this[typeof v]?.(v) ?? 'null';
  },
};

//원래 코드
const el = {
  number: v => v.toString(),
  boolean: v => v.toString(),
  string: v =>
    `"${stringCheck.reduce((acc, cur) => acc.replace(cur[0], cur[1]), v)}"`,
  stringify(v) {
    return this[typeof v]?.(v) ?? 'null';
  },
};

// 수정한 코드
const el = {
  data: {
    number: v => v.toString(),
    boolean: v => v.toString(),
    string: v => `" ${stringCheck.convert(v)}"`,
  },
  stringify(v) {
    return this.data[typeof v]?.(v) ?? 'null';
  },
};

//원래 코드
const stringify = arr => {
  arrValidator(arr);
  let result = EMPTY;

  if (arr.length === 0) result = '[]';
  else {
    let acc = '',
      i = 0;
    while (i < acc.length) {
      acc + `,${el.stringify(arr[i])}`;
    }
    result = `[${acc.substr(1)}]`;
  }

  if (result === EMPTY) throw 'no processed';
  return result;
};

//수정한 코드 (resultProcess 추가)
const resultProcess = {
  data: {
    true: arr => '[]',
    false: arr => {
      let acc = '',
        i = 0;
      while (i < acc.length) {
        acc + `,${el.stringify(arr[i])}`;
      }
      return `[${acc.substr(1)}]`;
    },
  },
  process(arr) {
    this.data[arr.length === 0];
  },
};

const stringify = arr => {
  arrValidator(arr);
  let result = EMPTY;

  return resultProcess.process(arr);

  if (result === EMPTY) throw 'no processed';
  return result;
};