Simple method to modify json keys casing to camelCase from snake_case

Question

I have lots of json parsing and all the json I am receiving is having keys in snake case like user_name . And for parsing I need it in camel case like userName .

The sample json file would look like this:

[{
   "user_id" : 1,
   "user_name" : "Abcd"
},
{
   "org_id" : 11,
   "org_name" : "some_name"
}
...
]

Expected output:

[{
   "userId" : 1,
   "userName" : "Abcd"
},
{
   "orgId" : 11,
   "orgName" : "some_name"
}
...
]

The json I am receiving is not having any particular fixed notation and it can be anything. But all the keys will be in snake case. And I need to convert it to camelCase.

What I cannot do is, find and replace, because it also replace snake casing strings in values as well.

Is there any easy method, which can do the same?

Answer 1

You can use npm package called: camelcase-keys-deep

https://www.npmjs.com/package/camelcase-keys-deep

Answer 2

You can do the following:

var keys = [];//this will contain the json with desired output
for(var i = 0;i<myObj.length;i++)//myObj is the variable that contains your json
{
    Object.keys(myObj[i]).forEach(function(key){
        if(keys.indexOf(key) == -1)
        {
            var newValue = {};
            var value = myObj[i][key];
            key = key.replace(/_([a-z])/g, function (g) { return g[1].toUpperCase(); });
            newValue[key] = value;
            keys.push(newValue);
        }   
    });

}
//console.log(keys);

Hope this helps :)

Answer 3

 var arr = [{ "user_id": 1, "user_name": "Abcd" }, { "org_id": 11, "org_name": "some_name" } ]; arr.forEach(a => { Object.keys(a).forEach(k => { newK = k.replace(/(\\_\\w)/g, (m) => m[1].toUpperCase()); a[newK] = a[k]; delete a[k]; }); }); console.log(arr); 

Answer 4

So AKSHAY JAIN 's implementation is pretty solid but it will delete the properties that are not in snake case. I fixed the implementation.

var arr = [{
  "user_id": 1,
  "user_name": "Abcd"
},
{
  "org_id": 11,
"org_name": "some_name"
},
{
  "personId": 12,
  "personName": "otherName"
}];

arr.forEach(a => {
    Object.keys(a).forEach(k => {
      newK = k.replace(/(\_\w)/g, (m) => m[1].toUpperCase());
      if (newK != k) {
        a[newK] = a[k];
        delete a[k];
      }
    });
  });

console.log(arr);

Answer 5

If u use lodash I would suggest my solution for this:

snake_case -> camelCase

function camelCaseDeep(anything) {
  const thing = _.cloneDeep(anything);

  if (
    _.isEmpty(thing) ||
    (!_.isObject(thing) && !_.isArray(thing))
  ) {
    return thing;
  }

  if (_.isArray(thing)) {
    const arr = thing;
    return arr.map(el => camelCaseDeep(el))
  }

  // thing can be only not empty object here
  const objWithMappedKeys = _.mapKeys(thing, (value, key) => _.camelCase(key));
  const objWithMappedValues = _.mapValues(objWithMappedKeys, value => camelCaseDeep(value));

  return objWithMappedValues;
}

camelCase -> snake_case

function snakeCaseDeep(anything) {
  const thing = _.cloneDeep(anything);

  if (
    _.isEmpty(thing) ||
    (!_.isObject(thing) && !_.isArray(thing))
  ) {
    return thing;
  }

  if (_.isArray(thing)) {
    const arr = thing;
    return arr.map(el => snakeCaseDeep(el))
  }

  // thing can be only not empty object here
  const objWithMappedKeys = _.mapKeys(thing, (value, key) => _.snakeCase(key));
  const objWithMappedValues = _.mapValues(objWithMappedKeys, value => snakeCaseDeep(value));

  return objWithMappedValues;
}