type-json-mapper

Introduction

Instead of directly using api data, we definitely require an adapter layer to transform data as needed. Furthermore, the adapter inverse the the data dependency from API server(API Server is considered uncontrollable and highly unreliable as data structure may be edit by backend coder for some specific purposes)to our adapter which becomes reliable. Thus, this library is created as the adapter. It also supports mock data.

Doc

中文文档

Get Started

npm install type-json-mapper --save

Example

Here is a complex example, hopefully could give you an idea of how to use it:

import { mapperProperty, deepMapperProperty, filterMapperProperty } from "type-json-mapper";

class Lesson {
  @mapperProperty('ClassName', 'string')
  public name: string;

  @mapperProperty('Teacher', 'string')
  public teacher: string;

  @mapperProperty('DateTime', 'datetime')
  public datetime: string;

  @mapperProperty('Date', 'date')
  public date: string;

  @mapperProperty('Time', 'time')
  public time: string;

  @mapperProperty('Compulsory', 'boolean')
  public compulsory: boolean;

  constructor() {
    this.name = '';
    this.teacher = '';
    this.datetime = '';
    this.date = '';
    this.time = '';
    this.compulsory = false;
  }
}

class Address {
  @mapperProperty('province', 'string')
  public province: string;
  @mapperProperty('city', 'string')
  public city: string;
  @mapperProperty('full_address', 'string')
  public fullAddress: string;

  constructor() {
    this.province = '';
    this.city = '';
    this.fullAddress = '';
  }
}

class Student {
  @mapperProperty('StudentID', 'string')
  public id: string;

  @mapperProperty('StudentName', 'string')
  public name: string;

  @mapperProperty('StudentAge', 'int')
  public age: number;

  @mapperProperty('NotFloat', 'float')
  public notFloat: number;

  @mapperProperty('NotANum', 'int')
  public notNum: number;

  @mapperProperty('UnknownType', 'String')
  public unknownType: string;

  @mapperProperty('Grade', 'float')
  public grade: number;

  @mapperProperty('AddressIds', 'string')
  public addressIds?: string[];

  @deepMapperProperty('Address', Address)
  public address?: Address;

  @deepMapperProperty('Lessons', Lesson)
  public lessons?: Lesson[];

  @filterMapperProperty('State', (val = 0) => {
    const map = { '0': '未知', '1': '读书中', '2': '辍学', '3': '毕业' };
    return map[`${val}`];
  })
  public status: string;

  public extra: string;

  constructor() {
    this.id = '';
    this.name = '';
    this.age = 0;
    this.notNum = 0;
    this.notFloat = 0;
    this.unknownType = '';
    this.grade = 0;
    this.addressIds = [];
    this.address = null;
    this.lessons = [];
    this.status = '';
    this.extra = '';
  }
}

Now here is what API server return, assume it is already parsed to JSON object.

const json = {
  StudentID: '123456',
  StudentName: '李子明',
  StudentAge: '10',
  NotANum: 'lol',
  NotFloat: 'def',
  UnknownType: 'funny',
  Grade: '98.6',
  AddressIds: [1, 2],
  Address: {
    province: '广东',
    city: '深圳',
    full_address: 'xxx小学三年二班'
  },
  Lessons: [
    {
      ClassName: '中国上下五千年',
      Teacher: '建国老师',
      DateTime: 1609430399000,
      Date: 1609430399000,
      Time: 1609430399000,
      Compulsory: 1
    },
    {
      ClassName: '古筝的魅力',
      Teacher: '美丽老师',
      DateTime: ''
    }
  ],
  State: 1,
  extra: '额外信息'
  }

Deserialize

Simply, just map it use following code.

import { deserialize } from 'type-json-mapper';
try {
  const student = deserialize(Student, json);
  console.log(student);
} catch(err) {
  console.error(err);
}

the result

{
  id: '123456',
  name: '李子明',
  age: 10,
  notNum: 'lol',
  notFloat: 'def',
  unknownType: 'funny',
  grade: 98.6,
  addressIds: ['1', '2'],
  address: { province: '广东', city: '深圳', fullAddress: 'xxx小学三年二班' },
  lessons: [
    {
      name: '中国上下五千年',
      teacher: '建国老师',
      datetime: '2020-12-31 23:59:59',
      date: '2020-12-31',
      time: '23:59:59',
      compulsory: true
    },
    {
      name: '古筝的魅力',
      teacher: '美丽老师',
      datetime: '',
      date: undefined,
      time: undefined,
      compulsory: undefined
    }
  ],
  status: '读书中',
  extra: '额外信息'
}

Serialize

import { serialize } from 'type-json-mapper';
try {
  const params = serialize(Student, student);
  console.log(params);
} catch(err) {
  console.error(err);
}

{
  StudentID: '123456',
  StudentName: '李子明',
  StudentAge: 10,
  NotANum: 'lol',
  NotFloat: 'def',
  UnknownType: 'funny',
  Grade: 98.6,
  AddressIds: [ '1', '2' ],
  Address: { province: '广东', city: '深圳', full_address: 'xxx小学三年二班' },
  Lessons: [
    {
      ClassName: '中国上下五千年',
      Teacher: '建国老师',
      DateTime: '2020-12-31 23:59:59',
      Date: '2020-12-31',
      Time: '23:59:59',
      Compulsory: true
    },
    { ClassName: '古筝的魅力', Teacher: '美丽老师', DateTime: '' }
  ],
  State: '读书中',
  extra: '额外信息'
}

Mock data

import { mock } from 'type-json-mapper';
const res = mock(Student, { fieldLength: { age: 20, grade: 4, name: 6 }, arrayFields: ['lessons'] });
console.dir(res);

{
  id: 'uBP2ug',
  name: 'EmcuTs',
  age: 7,
  notNum: 4,
  notFloat: 624.775,
  unknownType: '',
  grade: 537.3,
  addressIds: 'cjcpoC',
  address: { province: '1VSl9Z', city: 'tCtF9K', fullAddress: 'Ves3rZ' },
  lessons: [
    {
      name: 'm2WqeY',
      teacher: 'UdIuLT',
      datetime: '2024-03-17 03:54:59',
      date: '2024-03-17',
      time: '03:54:59',
      compulsory: false
    },
    {
      name: 'dCEoGG',
      teacher: 'gJrmkV',
      datetime: '2024-03-17 03:54:59',
      date: '2024-03-17',
      time: '03:54:59',
      compulsory: false
    },
    {
      name: 'JDVZqP',
      teacher: 'dV8ITf',
      datetime: '2024-03-17 03:54:59',
      date: '2024-03-17',
      time: '03:54:59',
      compulsory: false
    }
  ],
  status: '未知',
  extra: ''
}

Make sure the decorator is assigned a type

Test

npm run test