TypeScript custom validator

How I can an extend the validator with my validator functions? I do this:

interface Validator extends ExpressValidator.Validator {
    isArray: () => ExpressValidator.Validator;
}

export interface IBaseRequest extends ExpressValidator.RequestValidation, express.Request {
    checkBody: {
        (item: string | string[], message?: string): Validator,
        (schema: {}): Validator
    };
}

when create express app:

app.use(validator({
     customValidators: {
         isArray: (value: any) => {
                return Array.isArray(value);
         }
     }
}));

but I think it’s not a right solution. Can you help me or say how I can do this right.

[Britskiy]

@eliprand thank you! now all works fine 👍

[eliprand]

@Britskiy , Here is what I ended up doing:

Create a definition file (mine is ./definition.d.ts ) and add the following:

import 'express-validator';

declare module 'express-validator' {
    interface Validator {
        isPassword(): Validator;
    }
}

This will add isPassword() as a custom validator, provide intellisense and make sure things compile properly. Remember that you still have to actually register those custom validator during the bootstrapping of your application.

The definition file can be anything, anywhere, as long as it’s in the compilation path. It shouldn’t produce anything.