What is the process for validating a nested array that contains multiple types with class-validator?

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To validate a nested array that contains multiple types with class-validator, you need to follow these steps:

1. Create the classes for each nested object type in the array.

2. Create a class for the container object that will hold the array of nested objects.

3. Add an array property to this container class that will contain the nested objects. Declare this property as an array of type any, because the nested objects can be of different types.

4. Use the ArrayMinSize and ArrayMaxSize decorators to specify the minimum and maximum number of nested objects in the array.

5. Use the ArrayUnique and ValidateNested decorators to ensure that each nested object is unique and that it is of a valid type.

6. Add the appropriate validation decorators to each nested object class to ensure that all properties are valid.

7. Finally, you can validate the nested array using the validate function provided by class-validator.

Here is an example of the code:

import { IsString, IsNotEmpty, ArrayMinSize, ArrayMaxSize, ArrayUnique, ValidateNested } from 'class-validator';
import { Type } from 'class-transformer';

class NestedObject1 {
  @IsString()
  @IsNotEmpty()
  property1: string;

  // add more properties and validation decorators
}

class NestedObject2 {
  @IsString()
  @IsNotEmpty()
  property2: string;

  // add more properties and validation decorators
}

class ContainerObject {
  @ArrayMinSize(1)
  @ArrayMaxSize(10)
  @ArrayUnique()
  @ValidateNested({ each: true })
  @Type(() => [NestedObject1, NestedObject2])
  nestedObjects: any[];
  // Declare the array property as type 'any' to accommodate different object types.
}

// Example usage:
const container = new ContainerObject();
container.nestedObjects = [
  new NestedObject1(),
  new NestedObject2(),
  new NestedObject1(),
];
await validate(container);

This example validates an array of nested objects that can be of type NestedObject1 or NestedObject2. The array must have at least one object and no more than ten objects. Each nested object in the array must be unique and must pass its own validation requirements. The @ValidateNested and @Type decorators define the expected object types in the array.