In the application, I have defined two models. The first model is the movie model, and the second model is the user model. In the movie model, movie name is a unique field, and in the user model, email is a unique field. In the “duplicateKeyErrorHandler” function, the message is static, but I need a model name for a duplicate movie or duplicate email.

Duplicate error message is written in “duplicateKeyErrorHandler” function.

I am getting the same error message for duplicate movie names and duplicate user emails, but I need different messages for different models and unique fields.

Now error messages for duplicate movie and duplicate user email are same:
“message”: “There is already a movie with name The Matrix. Please use another name.”,

Expected messages should be like this:

for duplicate movie name
“message”: “There is already a movie with name ‘The Matrix’. Please use another name.”,

for duplicate user email
“message”: “There is already a email with this email [email protected]. Please use another email.”,

Error controller code is:

const CustomError = require('../utils/CustomError');

const castErrorHandler = (err) => {
    const msg = `Invalid value for ${err.path}: ${err.value}`;
    return new CustomError(msg, 400);
}

const duplicateKeyErrorHandler = (err) => {
    const msg = `There is already a movie with name ${err.keyValue.name}. Please use another name.`;
    return new CustomError(msg, 400);
}

const devErrors = (res, error) => {
    res.status(error.statusCode).json({
        status: error.status,
        message: error.message,
        stackTrace: error.stack,
        error: error
    });
}

const prodErrors = (res, error) => {
    if (error.isOperational) {
        res.status(error.statusCode).json({
            status: error.status,
            message: error.message
        });
    }
    else {
        res.status(500).json({
            status: 'error',
            message: 'Something went wrong! Please try again later.'
        });
    }
}

module.exports = (error, req, res, next) => {
    error.statusCode = error.statusCode || 500;
    error.status = error.status || 'error';

    if (process.env.NODE_ENV === "development") {
        if(error.name === "CastError") error = castErrorHandler(error);
        if(error.code === 11000) error = duplicateKeyErrorHandler(error);
        devErrors(res, error);
    } else if (process.env.NODE_ENV === "production") {
        if(error.name === "CastError") error = castErrorHandler(error);
        if(error.code === 11000) error = duplicateKeyErrorHandler(error);
        prodErrors(res, error);
    }
};

Duplicate field error response is:

{
    "status": "error",
    "message": "E11000 duplicate key error collection: node_practice_1.users index: email_1 dup key: { email: "[email protected]" }",
    "stackTrace": "MongoServerError: E11000 duplicate key error collection: node_practice_1.users index: email_1 dup key: { email: "[email protected]" }n    at InsertOneOperation.execute (D:\RND\Node-JS\node-practice-1\node_modules\mongodb\lib\operations\insert.js:51:19)n    at process.processTicksAndRejections (node:internal/process/task_queues:95:5)n    at async executeOperation (D:\RND\Node-JS\node-practice-1\node_modules\mongodb\lib\operations\execute_operation.js:136:16)n    at async Collection.insertOne (D:\RND\Node-JS\node-practice-1\node_modules\mongodb\lib\collection.js:155:16)",
    "error": {
        "errorResponse": {
            "index": 0,
            "code": 11000,
            "errmsg": "E11000 duplicate key error collection: node_practice_1.users index: email_1 dup key: { email: "[email protected]" }",
            "keyPattern": {
                "email": 1
            },
            "keyValue": {
                "email": "[email protected]"
            }
        },
        "index": 0,
        "code": 11000,
        "keyPattern": {
            "email": 1
        },
        "keyValue": {
            "email": "[email protected]"
        },
        "statusCode": 500,
        "status": "error"
    }
}