Reputation: 2436
I have the following DTO object in my NestJS controller as part of the request body:
export class UserPropertiesDto {
[key: string]: boolean;
}
E.g.: {campaignActive: true, metadataEnabled: false}
It's a key-value pair object
, where the key is a unique string
and its value is a boolean
.
I want to apply class-validator
annotations to ensure proper validations and transformations, but it keeps showing an error Decorators are not valid here
:
export class UserPropertiesDto {
@IsOptional()
@IsString() // `key` should be a string
@MaxLength(20) // `key` should have no more than 20 characters
@IsBoolean() // `value` has to be a `boolean`
[key: string]: boolean;
}
Could you, please, advice on the best way to do this:
boolean
Upvotes: 3
Views: 6216
Reputation: 3007
I suggest you to work with a custom validator, I tried to do something work for you:
iskeyvalue-validator.ts
import { ValidatorConstraint, ValidatorConstraintInterface,
ValidationArguments }
from
"class-validator";
import { Injectable } from '@nestjs/common';
@Injectable()
@ValidatorConstraint({ async: true })
export class IsKeyValueValidate implements ValidatorConstraintInterface {
async validate(colmunValue: Object, args: ValidationArguments) {
try {
if(this.isObject(colmunValue))
return false;
var isValidate = true;
Object.keys(colmunValue)
.forEach(function eachKey(key) {
if(key.length > 20 || typeof key != "string" || typeof colmunValue[key] !=
"boolean")
{
isValidate = false;
}
});
return isValidate ;
} catch (error) {
console.log(error);
}
}
isObject(objValue) {
return objValue && typeof objValue === 'object' && objValue.constructor === Object;
}
defaultMessage(args: ValidationArguments) { // here you can provide default error
message if validation failed
const params = args.constraints[0];
if (!params.message)
return `the ${args.property} is not validate`;
else
return params.message;
}
}
To implement it you have to add IsKeyValueValidate in the module providers :
providers: [...,IsKeyValueValidate],
and in your Dto:
@IsOptional()
@Validate(IsKeyValueValidate,
[ { message:"Not valdiate!"}] )
test: Object;
Upvotes: 2
Reputation: 1713
I'd advice to pay attention on custom validator. During validation it have access to all properties and values of the validated object.
All validation arguments you can pass as a second parameter and use them inside of validator to control flow.
export class Post {
@Validate(CustomTextLength, {
keyType: String,
maxLength: 20
...
})
title: string;
}
Upvotes: 1