How can I replace all keys of nested object in javascript

Question

      function renameKeys(obj, newKeys) {
        const keyValues = Object.keys(obj).map((key) => {
          let newKey = key + "1";
          if (Array.isArray(obj[key]) == false) {
            renameKeys(obj[key], newKeys);
          }
          console.log(newKey, "]", obj[key]);
          return {
            [newKey]: obj[key],
          };
        });
        return Object.assign({}, ...keyValues);
      }

      test = JSON.parse(
        '{"verifying_explanation":
               {"bus_stop":["1234"],
                "elementary_school":["1234"],
                "middle_school":["1234"],
                "high_school":["1234"]
               }
         }'
      );
      console.log(test);
      data = renameKeys(test, this);
      console.log(data);

It look like all keys changed in function, but it is not applied . I think because of copy principal. I have no idea how I can manipulate for keys. I want to replace all keys so that I apply i18n in my code.

So new key will be somethign like
let newKey = i18n.$t(key); This short code is just for test code. Please give me some ideas to solve this problem.

Nikhil Patil · Accepted Answer · 2020-12-23 07:33:02Z

2

You need to define your function to create new key value pairs and then form an object from these. Also, check if the value is an object, to recursively rename nested objects -

function renameKeys(obj) {
  const keyValues = Object.entries(obj).map(([key, value]) => {
    let newKey = key + "1";
    if (typeof value === 'object' && value !== null && !Array.isArray(value)) {
      value = renameKeys(value);
    }
    return [newKey, value];    
  });
  return Object.fromEntries(keyValues);
}

test = JSON.parse(
'{"verifying_explanation": {"bus_stop": ["1234"],"elementary_school": ["1234"],"middle_school": ["1234"],"high_school": ["1234"]}}'
);
console.log(test);
data = renameKeys(test, this);
console.log(data);

answered Dec 23, 2020 at 7:33

Nikhil Patil

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Comments

Kevin Zhang · Accepted Answer · 2020-12-23 07:19:54Z

0

You can't return new key-value pair in your function, instead of that, you just need to add new key to obj and delete old one.

function renameKeys(obj, newKeys) {
        Object.keys(obj).map((key) => {
          let newKey = key + "1";
          if (Array.isArray(obj[key]) == false) {
            renameKeys(obj[key], newKeys);
          }
          // console.log(newKey, "]", obj[key]);
          obj[newKey]=obj[key];
          delete obj[key];
        });
      }

      test = JSON.parse(
        `{"verifying_explanation":
               {"bus_stop":["1234"],
                "elementary_school":["1234"],
                "middle_school":["1234"],
                "high_school":["1234"]
               }
         }`
      );
      
      console.log(test);
      data = renameKeys(test, this);
      console.log(test);

answered Dec 23, 2020 at 7:19

Kevin Zhang

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3 Comments

Sammy Kim Over a year ago

I have one more question. How is this code works without delete replace keys example without delete?

Kevin Zhang Over a year ago

Regard that this is a recursive method, and look into this line: obj[key] = obj[key].map(obj => renameKeys(obj, newKeys)); It will apply the return value to obj at last.

Sammy Kim Over a year ago

Thanks a lot. I have less understand about map function

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