Basics

Options

Data Caster has only two general options that you can set to change basic behavior:

  • forceCamelCase
  • ignoreExcluded

forceCamelCase

This option is used to determine whether transform object's properties into camelCase-notation or not.

Default value: true

If its value is false no transformations will be applyed to properties names. This option can be changed only with initialization.

Note: If object's property ends with _id or _Id and forceCamelCase === true the result will be <property>ID. For example, user_id -> 'userID'

ignoreExcluded

This option allows temporarily switch off and on using excluded fields. This is useful for preparing data for server: if you don't want to send everything.

But, of course, it can be used during adapting phase as well via ignoreExcluded() method.

So, you can set your own options by using init() method:

import { DataCaster } from '@daminort/data-caster';

const dc = new DataCaster()
  .init({
    forceCamelCase: false,
    ignoreExcluded: true,
  });

Be careful if you are going to use init() during using DataCaster instance: this one cleans up all data you might set before.

Fields

In order to use DataCaster you need to describe every field you want to see in the result. To do it DataCaster offer special methods that named by types of fields they add.

For example, string(), int(), objectArray() and so on.

But all fields you are defining have certain set of properties:

  • type: type of field
  • originName: the name of property in origin object
  • resultName: the name of property in resulting object
  • adapter: will be invoked to coerce value during adapting phase
  • preAdapter: will be invoked before coercion during adapting phase
  • postAdapter: will be invoked right after coercion during adapting phase
  • reverter: will be invoked to coerce value during reverting phase
  • preReverter: will be invoked before coercion during reverting phase
  • postReverter: will be invoked right after coercion during reverting phase

Example:

import { DataCaster } from '@daminort/data-caster';

const serverData = {
  active_status: '-1',
};

const dc = new DataCaster()
  .bool('active_status', {
    resultName: 'isActive',
    adapter: (value) => +value > 0,
    reverter: (value) => value ? '1' : '-1',
  });

const result = dc.adapt(serverData);

// result
{
  isActive: false,
}

More examples you can get in the API reference section.

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