assignment-005.js

if (1) {
  // 1번과제 [1, 2, 3, 4, 5, 6, 7].filter(it=> it%2).map(it=>it*2) 7회로 해결하기 입니다.

  let cnt = 0;

  const generator = function* (arr) {
    for (let i = 0; i < arr.length; i++) {
      cnt++;
      if (arr[i] % 2) {
        yield arr[i] * 2;
      }
    }
  };

  const [...res] = generator([1, 2, 3, 4, 5, 6, 7]);
  console.log(res);
  console.log(cnt);
}


if (1) {
  // 2번 과제
  // https://gist.github.com/hikaMaeng/3944b4b75bf8a42f4814de0e8bb56e1d
  // 미완 코드 완성하기
  // 거의 유투브를 보며.. 보고 그대로 쳤네요 ㅠ
  
  const stringCheck = [
    [/[\r\n\l]/g, "\\n"],
    [/"/g, '\\"', [/\t/g, "\\t"]],
  ];

  const el = {
    number: (v) => v.toString(),
    boolean: (v) => v.toString(),
    string: (v) => {
      for (let i = 0; i < stringCheck.length; i++) {
        v = v.replace(stringCheck[0], stringCheck[1]);
      }
      return v;
    },
    stringify(v) {
      return this[typeof v]?.(v) ?? "null";
    },
  };

  const objEntries = function* (obj) {
    for (const k in obj) if (obj.hasOwnProperty(k)) yield [k, obj[k]];
  };

  const accToString = (isObject, acc) => {
    const [START, END] = isObject ? "{}" : "[]";

    let result = "";

    if (acc.prev) {
      let curr = acc;
      do {
        if (isObject) {
          result =
            `,"${curr.value[0]}":${el.stringify(curr.value[1])}` + result;
        } else {
          result = `,${curr.value}` + result;
        }
      } while ((curr = curr.prev));

      result = result.substr(1);
    }

    return START + result + END;
  };

  const recursive = (iter, isObject, acc, prev) => {
    const { done, value } = iter.next();

    if (!done) {
      const v = isObject ? value[1] : value;

      switch (true) {
        case Array.isArray(v):
          return recursive(v[Symbol.iterator](), false, null, {
            target: iter,
            isObject,
            k: isObject ? value[0] : "",
            acc,
            prev,
          });

        case v && typeof v == "object":
          return recursive(objEntries(v), true, null, {
            target: iter,
            isObject,
            k: isObject ? value[0] : "",
            acc,
            prev,
          });

        default:
          return recursive(iter, isObject, { prev: acc, value }, prev);
      }
    } else {
      const accStr = accToString(isObject, acc);

      if (prev) {
        return recursive(
          prev.target,
          prev.isObject,
          { prev: prev.acc, value: prev.isObject ? [prev.k, accStr] : accStr },
          prev.prev
        );
      } else {
        return accStr;
      }
    }
  };

  const stringify = (v) => {
    const iter = Array.isArray(v) ? v[Symbol.iterator]() : objEntries(v);
    const isObject = !Array.isArray(v);
    return recursive(iter, isObject, null, null);
  };

  stringify({ a: 3, b: 5, c: [1, 2, [3, 4, { a: 4, b: 5 }, 7], 3], d: 3 });
}

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