sinabakh/js-object-transform

Transform your objects to desired rich ones using declarative rules.

object-transform

Transform your objects to desired rich ones using declarative rules.

const transform = require('transformobject').transform;

const obj = {
  secret: 'Secret Data',
  username: 'John Doe',
  nested: {
    username: 'Nested John Doe',
  },
  'flat.nested.username': 'Flat John Doe',
  phoneNumber: '+989191331313',
  date: new Date(),
  nullField: null,
};

const transformer = {
  username: 'username',
  nestedUsername: 'nested.username',
  flatUsername: 'flat.nested.username',
  phone: {
    number: 'phoneNumber',
  },
  constantNumber: 4,
  booleanField: true,
  day: function (originObject) {
    return originObject.date.getDate();
  },
  nullField: 'nullField',
  undefinedField: 'unknownField',
  nonExistingNested: 'nested.username.verification.isVerified',  
};


const transformed = transform(obj, transformer);

// { username: 'John Doe',
//   nestedUsername: 'Nested John Doe',
//   flatUsername: 'Flat John Doe',
//   phone: { number: '+989191331313' },
//   constantNumber: 4,
//   booleanField: true,
//   day: 3,
//   nullField: null,
//   undefinedField: undefined,
//   nonExistingNested: undefined}

Options

Using strict option, transformer changes undefined fields to null fields, so they will not be omitted when stringified

strict

const transformed = transform(obj, transformer, { strict: true });

// { username: 'John Doe',
//   nestedUsername: 'Nested John Doe',
//   flatUsername: 'Flat John Doe',
//   phone: { number: '+989191331313' },
//   constantNumber: 4,
//   booleanField: true,
//   day: 3,
//   nullField: null,
//   undefinedField: null,
//   nonExistingNested: null}

source

Providing a source object will write the transformed values into the source instead of creating a new object

const transformed = transform(obj, transformer, { source: { a: 1, b: 2, house: { name: 'Brambles'} } });

// { 
//   a: 1,
//   b: 2,
//   house: { name: 'Brambles' },
//   username: 'John Doe',
//   nestedUsername: 'Nested John Doe',
//   flatUsername: 'Flat John Doe',
//   phone: { number: '+989191331313' },
//   constantNumber: 4,
//   booleanField: true,
//   day: 3,
//   nullField: null,
//   undefinedField: null,
//   nonExistingNested: null}

actions

Providing an actions object will allow the actions to be reused across transforms, this provides the ability to process fields using an array syntax to share functionality.

The array syntax works as follows:

The first field is the lookup, same as before, all additional fields are executed in order passing the result along the chain. ['username', 'undefinedIfEmptyString']

Example

const ucwords = require('ucwords'); // example npm install
const camelCase = require('lodash.camelcase'); // example npm install

const obj = {
  username: 'John Doe',
  nested: {
    username: 'Nested John Doe',
  },
};

const transformer = {
  username: ['username', 'camelCase', 'undefinedIfEmptyString'],
  nestedUsername: ['nested.username', 'ucwords', 'undefinedIfEmptyString'],
};

const transformed = transform(
  obj, 
  transformer, 
  {
    actions: {
      camelCase: value => camelCase(value),
      ucwords: value => ucwords(value),
      undefinedIfEmptyString: value => value === "" ? undefined : value,
    } 
  }
);

Actions can be combined with both strict and source. If an action is not defined but is used, a console warning will be logged.