sample.js


const obj = {
  obj1: "1111",
  obj2: "1111",
  obj3: "1111",
  obj4: {
    obj1: "1111",
    obj2: "1111",
  },
};

objToStr(obj);

function objToStr(sampleObj){
    const s_Json = JSON.stringify(sampleObj, null, 2);
    const line = s_Json.split('\n');

    line.forEach(function (val) {
        let keyAndValue = val.split(':');
        let left = keyAndValue[0].replace(/"/m, '');
        left = left.replace(/"/m, '');
        const right = keyAndValue[1] ? ':' + keyAndValue[1] : '';
        console.log(left + right + '\n');
    });
}

実行結果

{
  obj1: \"1111\",
  obj2: \"1111\",
  obj3: \"1111\",
  obj4: {
    obj1: \"1111\",
    obj2: \"1111\"
  }
}