waterloo-mapper

waterloo-mapper is object to object mapper

Example usage

Source object:

var src = {
    id: 1,
    name: 'Ibrahim',
    cars: [
        {id:1, brand: 'Ferrari', model: '458'},
        {id:2, brand: 'Lamborghini', model: 'Aventador'},
    ],
    address:{
        id: 1,
        country: 'Bulgaria',
        city: 'Razgrad',
        postCode: '7200'
    }
}

Destination object:

var dest = {
    id: 0,
    name: null,
    cars: [],
    address:{
        id: 0,
        country: null,
        city: null,
        postCode: null
    }
}

When source and destination have the same type we simply can map with:

import { Mapper } from 'waterloo-mapper';

new Mapper().from(src).to(dest).map();

//Destination object will be exact copy of the source object
{
    id: 1,
    name: 'Ibrahim',
    cars: [
        {id:1, brand: 'Ferrari', model: '458'},
        {id:2, brand: 'Lamborghini', model: 'Aventador'},
    ],
    address:{
        id: 1,
        country: 'Bulgaria',
        city: 'Razgrad',
        postCode: '7200'
    }
}

Actual mapping is triggered when we call .map()

Custom function mapping

Lets say we have fullAddress field at our destination object

var dest = {
    id: 0,
    name: null,
    fullAddress // here we want to get all address fields as single line
    address:{
        id: 0,
        ...
    }
}

import { Mapper } from 'waterloo-mapper';

//We can save the mapper instance and use it multiple times
//keeping the logic we applied for fullAddress

var mapper = new Mapper()
.for('fullAddress').use(src => `${src.address.country}, ${src.address.city}, ${src.address.postCode}`);

mapper.from(src).to(dest).map(); //Trigger the mapping

// Destination object after mapping will be:
{
    id: 1,
    name: 'Ibrahim',
    fullAddress: 'Bulgaria, Razgrad, 7200'
    ...
}

Nested mapping

Lets say we want the fullAddress field to be inside the address object this time

var dest = {
    id: 0,
    ...
    address:{
        id: 0,
        fullAddress: null // now we moved fullAddress inside adress
        ...
    }
}

import { Mapper } from 'waterloo-mapper';

// We create mapper for the address
// Here we will have the address object in 'use' 
// and as second parameter we will receive the parent object

var addressMapper = new Mapper()
.for('fullAddress').use((addr, parent) => `${addr.country}, ${addr.city}, ${addr.postCode}`); 

// Create mapper for the whole object and here we say for 'address' we want to use our 'addressMapper'

var mapper = new Mapper()
.for('address').use(addressMapper);


mapper.from(src).to(dest).map(); //Trigger the mapping

// Destination object after mapping will be:
{
    id: 1,
    name: 'Ibrahim'
    ...
    address: {
        id: 1,
        ...
        fullAddress: 'Bulgaria, Razgrad, 7200'
    },
}

Array mapping

If we dont set any 'use' array will be copied as it is

If we want a custom mapping for the array we can do like this:

var dest = {
    id: 0,
    ...
    cars: [],
    ...
}

import { Mapper } from 'waterloo-mapper';

// Lets say we want brand and model as single string
// Callback function passed to 'forAll' is called for each object in the array
// and the object from the current iterration is passed 

var mapper = new Mapper()
.for('cars').forAll(car => { return {id: car.id, name: car.brand + ' ' + car.model}; });

// Alternatively we can use 'use' to achive the same functionality as shown above
// but 'forAll' is bit more clear and less verbose
/*
.for('cars').use(obj => obj.cars.map(car => { 
    return {id: car.id, name: car.brand + ' ' + car.model}; 
}));
*/

mapper.from(src).to(dest).map(); //Triggering the mapping

// Destination object after mapping will be:
{
    id: 1,
    ...
    cars: [
        {id:1, name: 'Ferrari 458'},
        {id:2, name: 'Lamborghini Aventador'},
    ],
    ...
}

After Map

var mapper = new Mapper()
.afterMap((src, dst) => {
    // Called after mapping is finished
    // we have access to source and destination objects
    // Add any custom login here...
});

mapper.from(src).to(dest).map();