NestJS: validation des inputs DTO

Petite note rapide décrivant comment /bien/ valider les DTO entrantes pour les endpoints NestJS. En effet, il est facile d’oublier la bonne annotation et d’accepter des DTO non-valides.

Types primitifs

  @IsNumber() pace: number;
  @IsString() timezone: string;
  @IsBoolean() isActive: boolean;

Attributs facultatifs

  @IsBoolean() @IsOptional() isActive?: boolean;

Tableaux

  @IsArray() @ValidateNested({ each: true }) @Type(() => MyItemType) myArray: Array<MyItemType>;

Objets

  @IsNotEmptyObject() @ValidateNested() @Type(() => MyObjectType) myObject: MyObjectType;

Notes:
– @IsNotEmptyObject() is very much required: if absent, the absence of the whole ‘myObject’ in the DTO will be considered valid
– { each: true } in @ValidateNested is not adequate for Objects