ts-data-mapper
A typescript mapping tool supports mutual transforming between domain model and orm entity. In most case, domain model is not fully compatible with orm entity. you may need a mapping tool to convert model to entity when persisting and convert it back when accessing data.
installation
npm i ts-data-mapper
usage
- pseudo-code below is for describing usage, not working directly.
- assuming you have class Model and class Entity as below
class Model {
name: string
otherInfo: OtherType
}
@Entity()
class Entity {
@Column()
name: string
@Column()
otherInfo: string
}
- create a mapper (Model to Entity mapping)
import { Mapper } from 'ts-data-mapper'
const mapper = new Mapper(Model, Entity)
- define mapping rules. you can direct map property(i.e. name), and map a property using a mapping function(i.e. otherInfo), when direct mapping a property, you can also assign the second parameter(deep?: boolean) to true to deep clone corresponding property value. Methods below (directMap and map) has type check, property key intellisense and supports method chaining.
mapper.directMap('name').map('otherInfo', (model) => JSON.stringify(model.otherInfo));
if it has a bunch of property to map directly, you can also do below.
mapper.directMap(['name', 'gender'])
- map a source object to a target.
const model = new Model();
const entity = mapper.exec(model);
- (unnecessary) you may want to add a 'toEntity' method to class Model and a 'toModel' method to class Entity
class Model {
//...
toEntity(): Entity {
const mapper = new Mapper(Model, Entity).directMap('name').map('otherInfo', (model) => JSON.stringify(model.otherInfo));
return mapper.exec(this);
}
}
class Entity {
//...
toModel(): Model {
const mapper = new Mapper(Entity, Model).directMap('name').map('otherInfo', (model) => JSON.parse(model.otherInfo));
return mapper.exec(this);
}
}
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