Transform all keys in array from underscore to camel case in js

Question

So, I need to transform all keys in array from underscore to camel space in js. That is what I need to do before send form to server. I'm using Angular.js and I want to represent it as a filter (but I think it's not rly important in this case). Anyway, here is a function I've created.

.filter('underscoreToCamelKeys', function () {
        return function (data) {

            var tmp = [];
            function keyReverse(array) {
                angular.forEach(array, function (value, key) {
                        tmp[value] = underscoreToCamelcase(key);
                });

                return tmp;
            }

            var new_obj = {};
            for (var prop in keyReverse(data)) {
                if(tmp.hasOwnProperty(prop)) {
                    new_obj[tmp[prop]] = prop;
                }
            }
            return new_obj;
        };

        function underscoreToCamelcase (string) {
            return string.replace(/(\_\w)/g, function(m){
                return m[1].toUpperCase();
            });
        }
    })

Here I will try to explain how it works, because it looks terrible at first.

underscoreToCamelcase function just reverting any string in underscore to came case, except first character (like this some_string => someString )

So, as I said earlier, I should revert all keys to camel case, but as you understant we can't simply write

date[key] = underscoreToCamelcase(key)

so keyReverse function returns a reverted array, here is example

some_key => value

will be

value => someKey

and for the last I simply reverting keys and values back, to get this

someKey => value

But, as you already may understand, I got a problem, if in array exists the same values, those data will be dissapear

array

some_key1 => value , some_key2 => value

returns as

someKey2 => value

So how can I fix that? I have a suggestion to check if those value exists and if it is add some special substring, like this

some_key1 => value , some_key2 => value

value => someKey1 , zx99value => someKey2

and after all parse it for zx99, but it I think I`m going crazy... Maybe some one have a better solution in this case?

Important! Them main problem is not just to transform some string to camel case, but do it with array keys!

Answer 1

If you use an existing library to do the camelCase transform, you can then reduce an object like so

import {camelCase} from 'lodash/string'

const camelCaseKeys = (obj) =>
  Object.keys(obj).reduce((ccObj, field) => ({
    ...ccObj,
    [camelCase(field)]: obj[field]
  }), {})

Answer 2

.filter('underscoreToCamelKeys', function () {
        return function (data) {

            var tmp = {};
            angular.forEach(data, function (value, key) {
                var tmpvalue = underscoreToCamelcase(key);
                tmp[tmpvalue] = value;
            });

            return tmp;
        };

        function underscoreToCamelcase (string) {
            return string.replace(/(\_\w)/g, function(m){
                return m[1].toUpperCase();
            });
        }
    })

thanks to ryanlutgen

Answer 3

As an alternative solution, you could use the optional replacer parameter of the JSON.stringify method.

var result = JSON.stringify(myVal, function (key, value) {

  if (value && typeof value === 'object') {
    var replacement = {};
    for (var k in value) {
      if (Object.hasOwnProperty.call(value, k)) {
        replacement[underscoreToCamelcase(k)] = value[k];
      }
    }
    return replacement;
  }

  return value;
});

Of course you'll end up with a string and have to call JSON.parse to get the object.