joi_1.default.validate is not a function

Question

I want to validate my Express routes before calling the controller logic. I use joi and created a validator which is able to validate the Request object against the schema object

import { Request, Response, NextFunction } from 'express';
import joi, { SchemaLike, ValidationError, ValidationResult } from '@hapi/joi';
import { injectable } from 'inversify';

@injectable()
export abstract class RequestValidator {
    protected validateRequest = (validationSchema: SchemaLike, request: Request, response: Response, next: NextFunction): void => {
        const validationResult: ValidationResult<Request> = joi.validate(request, validationSchema, {
            abortEarly: false
        });

        const { error }: { error: ValidationError } = validationResult;

        if (error) {
            response.status(400).json({
                message: 'The request validation failed.',
                details: error.details
            });
        } else {
            next();
        }
    }
}

Next I created a deriving class which creates the validationSchema and calls the validateRequest method. For the sake of simplicity I will show the "deleteUserById" validation

import { Request, Response, NextFunction } from 'express';
import joi, { SchemaLike } from '@hapi/joi';
import { injectable } from 'inversify';

import { RequestValidator } from './RequestValidator';

@injectable()
export class UserRequestValidator extends RequestValidator {
    public deleteUserByIdValidation = async (request: Request, response: Response, next: NextFunction): Promise<void> => {
        const validationSchema: SchemaLike = joi.object().keys({
            params: joi.object().keys({
                id: joi.number().required(),
            })
        });

        this.validateRequest(validationSchema, request, response, next);
    }
}

Important note: I create the SchemaLike that way because some routes might have params, body, query which need to get validated in one run.

When calling the Route

DELETE /users/1

the validation always fails. I get this error

UnhandledPromiseRejectionWarning: TypeError: joi_1.default.validate is not a function

The error occurs with every validation, whether called correctly or not. Does someone know how to fix it?

Answer 1

You fix it by changing joi.validate(request, validationSchema to validationSchema.validate(request As joi.validate() is no longer supported in v16. It is clearly documented in the API docs and release notes.