Ensuring the Accuracy of String Literal Types using class-validator

Question

Ensuring the Accuracy of String Literal Types using class-validator

Consider the following type definition:

export type BranchOperatorRole = 'none' | 'seller' | 'operator' | 'administrator';

Which Class-Validator decorator should I use to ensure that a property matches one of these values?

import { IsEmail, IsString, Contains } from "class-validator";

export type BranchOperatorRole = 'none' | 'seller' | 'operator' | 'administrator';

export class AddBranchOperatorRequest extends User {

    @IsEmail()
    email: string;

    @Contains(BranchOperatorRole )
    role: BranchOperatorRole;

}

typescript class-validator

Answer 1

Answer №1

const userRoles = ['none', 'seller', 'operator', 'administrator'] as const;
export type BranchOperatorRole = typeof userRoles[number];

export class AddBranchOperatorRequest extends User {

    @IsEmail()
    emailAddress: string;

    @IsIn(userRoles)
    role: BranchOperatorRole;

}

Answer 2

const userRoles = ['none', 'seller', 'operator', 'administrator'] as const;
export type BranchOperatorRole = typeof userRoles[number];

export class AddBranchOperatorRequest extends User {

    @IsEmail()
    emailAddress: string;

    @IsIn(userRoles)
    role: BranchOperatorRole;

}

Answer 3

Answer №2

When it comes to validation, relying on Types at runtime is not feasible due to their disappearance. A common approach is to create an Enum and utilize the IsEnum decorator for validation. Check out this example for reference.

For your specific scenario, consider implementing something like the following:

export enum BranchOperatorRoleEnum = {
  none=1,
  seller=2,
  // other
}

class AddBranchOperatorRequest {
    @IsEnum(BranchOperatorRoleEnum)
    role: BranchOperatorRole;
}

If preferred, you can also use an array instead of an enum:

export type BranchOperatorRole = 'none' | 'seller' | 'operator' | 'administrator';

export const BranchOperatorRoles: BranchOperatorRole[] = [
  'none',
  'seller',
  // other
]

class AddBranchOperatorRequest {
    @IsEnum(BranchOperatorRoles)
    role: BranchOperatorRole;
}

Answer 4

When it comes to validation, relying on Types at runtime is not feasible due to their disappearance. A common approach is to create an Enum and utilize the IsEnum decorator for validation. Check out this example for reference.

For your specific scenario, consider implementing something like the following:

export enum BranchOperatorRoleEnum = {
  none=1,
  seller=2,
  // other
}

class AddBranchOperatorRequest {
    @IsEnum(BranchOperatorRoleEnum)
    role: BranchOperatorRole;
}

If preferred, you can also use an array instead of an enum:

export type BranchOperatorRole = 'none' | 'seller' | 'operator' | 'administrator';

export const BranchOperatorRoles: BranchOperatorRole[] = [
  'none',
  'seller',
  // other
]

class AddBranchOperatorRequest {
    @IsEnum(BranchOperatorRoles)
    role: BranchOperatorRole;
}

Ensuring the Accuracy of String Literal Types using class-validator

Answer №1

Answer №2

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