class-converter

English | 简体中文

class-converter is used to convert a plain object to a class instance and the reverse process.

There is a simple example:

import { property, toClass } from 'class-convert';

class UserModel {
  @property('i')
  id: number;

  @property()
  name: string;
}

const userRaw = {
  i: 1234,
  name: 'name',
};

// use toClass to convert plain object to class
const userModel = toClass(userRaw, UserModel);
// you will get a class, just like below one
{
  id: 1234,
  name: 'name',
}

you can see a more complex example here

Installation

npm i class-converter --save

Changes

You can click here to find the details of breaking changes.

Usage Examples

Work with nested object/array

If you try to convert objects that have nested objects/arrays, you need to provide the type of object. If the value of the property of your object is an array, it will be converted all items in that array to target type automatically.

Example:

class NestedModel {
  @property('e', UserModel)
  employees: UserModel[];

  @typed(UserModel)
  @property('u')
  user: UserModel;
}

const model = toClass(
  {
    e: [
      { i: 1, n: 'n1' },
      { i: 2, n: 'n2' },
    ],
    u: {
      i: 1,
      n: 'name',
    }
  },
  NestedModel,
);
// you will get like this
{
  employees: [
    { id: 1, name: 'n1' },
    { id: 2, name: 'n2' },
  ],
  user: {
    id: 1,
    name: 'name'
  }
}

const model = toPlain(
  {
    employees: [
      { id: 1, name: 'n1' },
      { id: 2, name: 'n2' },
    ],
    user: {
      id: 1,
      name: 'name'
    }
  },
  NestedModel,
);
// you will get like this
{
  e: [
    { i: 1, n: 'n1' },
    { i: 2, n: 'n2' },
  ],
  u: {
    i: 1,
    n: 'name'
  }
}

Additional data conversion

import * as moment from 'moment';

export class EduModel {
  @property('i')
  id: number;

  @property('crt')
  @deserialize(value => moment(value).format('YYYY-MM-DD HH:mm:ss'))
  createTime: string;
}

Require for other properties

class EmailModel {
  @property('s')
  site: string;

  @property('e')
  @deserialize((value, _instance, origin) => `${value}@${origin.s}`)
  email: string;
}

Methods

toClass(raw, clazzType, options?) / toClasses(raws, clazzType, options?)

Convert an object to a class instance

• raw / raws <Object|Array<Object>> An raw object or an array of raw object
• clazzType <Class> Constructor of the target class
• options? <Object> convert config
  • ignoreDeserializer <Boolean> don't call deserializer(@deserialize) if true
  • ignoreBeforeDeserializer <Boolean> don't call beforeDeserializer(@beforeDeserialize) if true
  • distinguishNullAndUndefined <Boolean> distinguish null and undefined if true

Example:

const userRaw = {
  i: 1234,
  name: 'name',
};
const userRaws = [
  {
    i: 1000,
    name: 'name1',
  },
  {
    i: 2000,
    name: 'name2',
  },
];
const userModel = toClass(userRaw, UserModel);
const userModels = toClasses(userRaws, UserModel);

toPlain(instance, clazzType, options?) / toPlains(instances, clazzType, options?)

convert an object or a class instance to a raw object

• instance / instances <Object|Array<Object>> An object|instance or array of object|instance
• clazzType <Class> Constructor of the target class
• options? <Object> convert config
  • ignoreSerializer <Boolean> don't call serializer(@serialize) if true
  • ignoreAfterSerializer <Boolean> don't call afterSerializer(@afterSerialize) if true
  • distinguishNullAndUndefined <Boolean> distinguish null and undefined if true

Example:

const userModel = {
  id: 1234,
  name: 'name',
};
const userModels = [
  {
    id: 1000,
    name: 'name1',
  },
  {
    id: 2000,
    name: 'name2',
  },
];
const userRaw = toPlain(userModel, UserModel);
const userRaws = toPlains(userModels, UserModel);

All Property Decorators

The order in which these decorator's are invoked during the transformation:

• toClass/toClasses: beforeDeserializer => typed(convert to an instance) => deserializer
• toPlain/toPlains: serializer => typed(convert to a object) => afterSerializer

property(originalKey?, clazzType?, optional = false)

Convert a original key to your customized key, like n => name

• originalKey <string> A key of a raw object, default current class key
• clazzType <Class> Constructor its value to a target class instance automatically
• optional <Boolean> Optional in a raw object

Example:

class PropertyModel {
  @property('i')
  id: number;

  @property()
  name: string;

  @property('u', UserModel)
  user: UserModel;

  @property('t', null, true)
  timeStamp: number;
}

const model = toClass({ i: 234, name: 'property', u: { i: 123, n: 'name' } }, PropertyModel);
// you will get like this
{
  id: 234,
  name: 'property',
  user: {
    id: 123,
    name: 'name'
  }
}

typed(clazzType)

Set a target class type to a property, as same as the second parameter of property decorator

• clazzType <Class> Constructor its value to a target class instance automatically

Example:

// as same as @property('n', UserModel)
class TypedModel {
  @typed(UserModel)
  @property('u')
  user: UserModel;
}

const model = toClass({ u: { i: 123, n: 'name' } }, TypedModel);
// you will get like this
{
  user: {
    id: 123,
    name: 'name'
  }
}

optional()

Set a optional setting to a property, as same as the third parameter of property decorator

Example:

// as same as @property('n', null, true)
class OptionalModel {
  @optional()
  @property('n')
  name: string;
}

const model = toClass({}, OptionalModel);
// you will get like this
{
}

const model = toClass({ n: 'name' }, OptionalModel);
// you will get like this
{
  name: 'name';
}

const model = toClass(
  {
    e: [
      { i: 1, n: 'n1' },
      { i: 2, n: 'n2' },
    ],
  },
  OptionalModel,
);
// you will get like this
{
  employees: [
    { id: 1, name: 'n1' },
    { id: 2, name: 'n2' },
  ],
}

const model = toPlain(
  {
    employees: [
      { id: 1, name: 'n1' },
      { id: 2, name: 'n2' },
    ],
  },
  OptionalModel,
);
// you will get like this
{
  e: [
    { i: 1, n: 'n1' },
    { i: 2, n: 'n2' },
  ],
}

defaultVal(val)

set a default value to current property

• val <Any> default value

Example:

class DefaultValModel {
  @defaultVal(0)
  @property('i')
  id: number;
}

const model = toClass({}, DefaultValModel);
// you will get like this
{
  id: 0;
}

const raw = toPLain({}, DefaultValModel);
// you will get like this
{
  i: 0;
}

serializeTarget()

use the value of the current property when call toPlain function.

Example:

class SerializeTargetModel {
  @serializeTarget()
  @property('n')
  name: string;

  @property('n')
  nick: string;
}

const raw = toPlain(
  {
    name: 'name',
    nick: 'nick',
  },
  SerializeTargetModel,
);

// you will get like this
{
  n: 'name';
}

beforeDeserialize(beforeDeserializer, disallowIgnoreBeforeDeserializer = false)

Convert original value to a target form data, it happened before deserializer

• beforeDeserializer <(value: any, instance: any, origin: any) => any>
  • value <Any> The value corresponding to the current key in a raw object
  • instance <Instance> An instance(half-baked) of current class
  • origin <Object> A raw object
• disallowIgnoreBeforeDeserializer <Boolean> Force call beforeDeserializer(@beforeDeserialize) when call toClass if true, default false

Example:

class BeforeDeserializeModel {
  @beforeDeserialize((value: any) => JSON.parse(value))
  @property('m')
  mail: object;
}

toClass(
  {
    m: '{"id":123}',
  },
  BeforeDeserializeModel,
);

// you will get like this
{
  mail: { id: 123 },
};

deserialize(deserializer, disallowIgnoreDeserializer =false)

Deserialize original value to customized data, it only support when use toClass/toClasses

• deserializer (value: any, instance: any, origin: any) => any
  • value <Any> The value(result of beforeDeserializer/typed) corresponding to the current key in a raw object
  • instance <Instance> An instance(half-baked) of current class
  • origin <Object> A raw object
• disallowIgnoreDeserializer <Boolean> Force call deserializer(@deserialize) when call toClass if true, default false

Example:

class DeserializeModel {
  @deserialize((value: string) => `${value}@xxx.com`)
  @property('m')
  mail: string;
}

toClass(
  {
    m: 'mail',
  },
  DeserializeModel,
);

// you will get like this
{
  mail: '[e-mail]',
};

serialize(serializer, disallowIgnoreSerializer = false)

Serialize customized value to original value, it only support when use toPlain/toPlains

• serializer (value: any, instance: any, origin: any) => any
  • value <Any> The value corresponding to the current key in a instance
  • instance <Instance> An instance of current class
  • origin <Object> A raw object(half-baked)
• disallowIgnoreSerializer <Boolean> Force call serializer(@serialize) when call toPlain if true, default false

Example:

class SerializeModel {
  @serialize((mail: string) => mail.replace('@xxx.com', ''))
  @property('e')
  mail: string;
}

toPlain(
  {
    mail: '[e-mail]',
  },
  SerializeModel,
);

// you will get like this
{
  e: '[e-mail]',
}

afterSerialize(afterSerializer, disallowIgnoreAfterSerializer = false)

Convert a key/value in instance to a target form data, it happened after serializer only

• afterSerializer (value: any, instance: any, origin: any) => any
  • value <Any> The value(result of serializer/typed) corresponding to the current key in a instance
  • instance <Instance> An instance of current class
  • origin <Object> A raw object(half-baked)
• disallowIgnoreAfterSerializer <Boolean> Force call afterSerializer(@afterSerialize) when call toPlain if true, default false

Example:

class AfterSerializeModel {
  @afterSerialize((mail: string) => JSON.stringify(mail))
  @property('e')
  mail: string;
}

toPlain(
  {
    mail: { id: 1000 },
  },
  SerializeModel,
);

// you will get like this
{
  e: '{"id":1000}',
};

Tests

npm run test

License

MIT