@uxland/object-mapper

UXL Object Mapper

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Installation

npm i @uxland/object-mapper

Usage

A serializer is composed by:

• from: property of input object to serialize
• to (optional): destination property to which input object property defined in from will be serialized
• serializerFn (optional): serialization function used to serialize input following output[to] = serializerFn(input[from])
• deserializerFn (optional): deserialization function used to deserialize output following input[from] = deserializerFn(output[to])

Object serialization

from and to properties can be a property name or a path.

const input = {foo: 'bar'};
const serializers = [{from: 'foo', to: 'FOO'}];
serialize(input, serializers); // {FOO: 'bar'};

const input = {foo: {baz: 'bar'}};
const serializers = [{from: 'foo.baz', to: 'FOO'}];
serialize(input, serializers); // {FOO: 'bar'};

to property is optional. When not provided, destination property will be the same as the origin:

const input = {foo: 'bar', qux: 'quz'};
const serializers = [{from: 'foo', to: 'FOO'}, {from: 'qux'}];
serialize(input, serializers); // {FOO: 'bar', qux: 'quz'}

Changing data

serializerFn is used to change input data

const input = {foo: 'bar'};
const serializers = [{from: 'foo', serializerFn: value => value.toUpperCase()}];
serialize(input, serializers); // {foo: 'BAR'};

Multidestination serialization

to property can be used to map input data into multiple output properties

const input = {foo: 'bar'};
const serializers = [{from: 'foo', to: ['baz', 'qux']}];
serialize(input, serializers); // {baz: 'bar', qux: 'bar'};

Multiorigin serialization

When defining from as a property array, and to as a single property, a serializerFn must be provided in order to merge input data into a single output

const input = {name: 'foo', surname: 'bar'};
const serializers = [{from: ['name', 'surname'], to: 'fullname', serializerFn: (name, surname) => `${name} ${surname}`}];
serialize(input, serializers); // {fullname: 'foo bar'};

Sub-serialization

Due to its recursive capability, it is possible to define serializers within serializers in order to serialize nested objects

const input = {foo: [{qux: 'quz', bar: 'baz'}]};
const serializers = [{from: 'foo', to: 'FOO', serializers: [{from: 'qux', to: 'QUX'}, {from: 'bar', to: 'BAR'}]}];
serialize(input, serializers); // {FOO: [{QUX: 'quz', BAR: 'baz'}]};

const input = {foo: {qux: 'quz', bar: 'baz'}};
const serializers = [{from: 'foo', to: 'FOO', serializers: [{from: 'qux', to: 'QUX'}, {from: 'bar', to: 'BAR'}]}];
serialize(input, serializers); // {FOO: {QUX: 'quz', BAR: 'baz'}};

Deserialization

It is possible to use the same serializers array to deserialize output. There are some exceptions that are listed in TIC.

const input = {name: 'foo', surname: 'bar'};
const serializers = [{from: ['name', 'surname'], to: 'fullname', serializerFn: (name, surname) => `${name} ${surname}`, deserializerFn: (fullname) => fullname.split(' ')}];
const output = serialize(input, serializers); // {fullname: 'foo bar'};
deserialize(output, serializers); // {name: 'foo', surname: 'bar'}

TIC

One premise must be followed when using the same serializers array for serialize and deserialize: you cannot change serialize object result structure if deserialization is going to be used.

Also, be aware that changing input structure with serialize can cause inconsistencies and deserialization could be impossible since serializerFn and deserializerFn cannot access parent data information

Working example

const input = {foo: {baz: 'bar'}};
const serializers = [{from: 'foo.baz', to: 'baz'}];
const output = serialize(input, serializers); // {baz: 'bar'};
deserialize(output, serializers); // {foo: {baz: 'bar'}};

Serialization broken

const input = {foo: 'bar'};
const serializers = [{from: 'foo', serializers: [{from: 'bar'}]}];
const output = serialize(input, serializers); // {foo: {bar: undefined}};
// This cannot be deserialized