I have a nodejs
REST API backend running the nestjs
framework, using typeORM as ORM for my entities.
Coming from a C#/Entity Framework
background, I am very used to have my Dtos mapped to the database entities.
Is there a similar approach with typeORM?
I have seen the automapper-ts library, but those magic strings in the map declarations look kind of scary... Basically it would be amazing if I could :
let user: TypeORMUserEntity = mapper.map<TypeORMUserEntity>(userDto);
What is the way to do this (or any alternative with same result) in nodejs/typeorm backend environment?
You can use class-transformer library. You can use it with class-validator to cast and validate POST parameters.
Example:
@Exclude()
class SkillNewDto {
@Expose()
@ApiModelProperty({ required: true })
@IsString()
@MaxLength(60)
name: string;
@Expose()
@ApiModelProperty({
required: true,
type: Number,
isArray: true,
})
@IsArray()
@IsInt({ each: true })
@IsOptional()
categories: number[];
}
Exclude
and Expose
here are from class-transform
to avoid additional fields.
IsString
, IsArray
, IsOptional
, IsInt
, MaxLength
are from class-validator
.
ApiModelProperty
is for Swagger documentation
And then
const skillDto = plainToClass(SkillNewDto, body);
const errors = await validate(skillDto);
if (errors.length) {
throw new BadRequestException('Invalid skill', this.modelHelper.modelErrorsToReadable(errors));
}