assignment-004.js

if (1) {

  // 꼬리재귀..
  const stringCheck = [
    [/[\r\n\l]/g, "\\n"],
    [/"/g, '\\"', [/\t/g, "\\t"]],
  ];
  const el = {
    number: (v) => v.toString(),
    boolean: (v) => v.toString(),
    string: (v, isObjectValue) => {
      for (let i = 0; i < stringCheck.length; i++) {
        v = v.replace(stringCheck[0], stringCheck[1]);
      }

      if (isObjectValue) {
        v = `\"${v}\"`;
      }

      return v;
    },
    stringify(v, isObjectValue) {
      return this[typeof v]?.(v, isObjectValue) ?? "null";
    },
  };

  const arrToString = (arr) => {
    let str = "";
    for (const v of arr) str += `,${v}`;

    return `[${str.substr(1)}]`;
  };

  const objectToString = (arr) => {
    let str = "";
    for (const objElement of arr)
      str += `,\"${objElement[0]}\":${el.stringify(objElement[1], true)}`;

    return `{${str.substr(1)}}`;
  };

  const recursive = (arr, acc, i, isObject, stack) => {
    if (i < arr.length) {
      switch (true) {
        case arr[i].constructor == ({}).constructor:
          stack.push([arr, acc, i + 1, false]);
          return recursive(Object.entries(arr[i]), [], 0, true, stack);
        case Array.isArray(arr[i]):
          if (isObject) {
            acc.push(arr[i]);
            return recursive(arr, acc, i + 1, isObject, stack);
          } else {
            stack.push([arr, acc, i + 1, false]);
            return recursive(arr[i], [], 0, false, stack);
          }
        default:
          acc.push(el.stringify(arr[i]));
          return recursive(arr, acc, i + 1, isObject, stack);
      }
    } else {
      let accStr = "";
      if (isObject) {
        accStr = objectToString(acc);
      } else {
        accStr = arrToString(acc);
      }

      const pre = stack.pop();

      if (pre) {
        const [prevArr, prevAcc, prevIndex, isObject] = pre;
        prevAcc.push(accStr);

        recursive(prevArr, prevAcc, prevIndex, isObject, stack);
      } else {
        return accStr;
      }
    }
  };

  const stringify = (arr) => {
    if (!Array.isArray(arr)) throw "Invalid arr";
    return recursive(arr, [], 0, false, []);
  };

  stringify([1,2,{ name: "jjoir", age: 38 },[4, 5, 6],{ name: "good", age: 12, isObject: true },]);
  
}

74번째줄이 잘못되었는데 정상작동함?