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How to CamelCase Keys of an Object in JavaScript or Node.js

Interacting with data from third-party sources like APIs comes with challenges. You’re not in control of the data format and style. Sometimes, you wish to transform the data to your preferred style.

This tutorial shows you how to transform the keys of an object into camelCase format.

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CamelCase All Keys of an Object in JavaScript

We at Future Studio use camelCase as our preferred styling for object keys. External resources may not use camelCase and instead prefer snake_case.

You may want to normalize an object’s keys when interacting with APIs using snake_case. The following code snippet shows a camelCaseKeys function transforming all top-level object keys from their current format to camelCase:

const Str = require('@supercharge/strings')

/**
 * Translate all top-level keys of the given `object` to camelCase.
 *
 * @param {Object} object
 *
 * @returns {Object}
 */
function camelCaseKeys (object) {  
  return Object
    .entries(object)
    .reduce((carry, [key, value]) => {
      carry[Str(key).camel().get()] = value

      return carry
    }, {})
}

Modern browsers and Node.js support the Object.entries() method returning an array of the object’s key-value pairs. Then you can iterate over these pairs using Array#reduce() to create a new object following the desired coding style.

Here’s an example camel-casing all top-level keys of an object:

const fileImport = {  
  File_Location: '/user/marcus/downloads/data_import.xlsx',
  Created_At: 1610685464300,
  Nested: {
    // the `camelCaseKeys` function does not touch nested objects
  }
}

const camelCasedFileImport = camelCaseKeys(fileImport)  
// {
//   fileLocation: '/user/marcus/downloads/data_import.xlsx',
//   createdAt: 1610685464300,
//   nested: { … } 
// }

About the @supercharge/strings Package

I’m the maintainer of the @supercharge/strings package providing convenient string utilities. This package comes in handy when transforming a given string value to camelCase because it removes all special characters like whitespaces, dashes, exclamation marks, and so on:

const Str = require('@supercharge/strings')

const camelCased = Str('Hello Marcus').camel().get()  
// 'helloMarcus'

Enjoy!

Mentioned Resources

Marcus Pöhls

Marcus is a fullstack JS developer. He’s passionate about the hapi framework for Node.js and loves to build web apps and APIs. Creator of Futureflix and the “learn hapi” learning path.

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