CODEWITHSUNDEEP
node.jsecmascript-6
Kurt Van den Branden
Kurt Van den Branden

Reputation: 12934

Module.exports: is not a constructor error

Can someone explain why the first export throws a is not a constructor error, while the second export works? 

// Throws a `is not a constructor` error
module.exports = {
    Person: function () {
        constructor()
        {
            this.firstname;
            this.lastname;
        }
    }
}

// Works
class Person {
    constructor()
    {
       this.firstname = '';
       this.lastname = '';
    }
}
module.exports = Person;

// Usage:
const Person = require("person");
let person = new Person();

Upvotes: 5

Views: 5889

Answers (1)

Jonas Wilms
Jonas Wilms

Reputation: 138234

Because the first time you actually export an object containing a property:

  module.exports = { /*...*/ };

And you can't construct that object. However you could get the Person property and construct that:

 const Person = require("person").Person;
 new Person();

You could also destructure the imported object:

 const { Person } = require("person");
 new Person();

... but that only makes sense if there are other things exported there otherwise I would go with v2.

Upvotes: 6

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