Question

I have this module of javascript

var data = [

    {id: 1, firstName: 'John', lastName: 'Smith'},

    {id: 2, firstName: 'Jane', lastName: 'Smith'},

    {id: 3, firstName: 'John', lastName: 'Doe'}

];

module.exports.setid =

    function (value) {

        data.id = value;

};

module.exports.getid =

function () {

        return data.id;

    };

module.exports.setFirstName =

function (value) {

        data.firstName = value;

    };

module.exports.getFirstName =

function () {

        return data.firstName;

    };

module.exports.setLastName =

function (value) {

        data.lastName = value;

    };

I wrote the following to get all first and last names to show but the only out put i get

var foo = require('./EmployeeModule_v1');

console.log(foo.getFirstName(),

                     foo.getLastName(Smith));

out put

PS C:\Users\play_\OneDrive\Documents\scchool\Server_side\m1> node hw1a
undefined undefined

Answer 1

Your current program is outputting undefined because your data is an array of objects. You are returning data.firstname but you are not giving from which index it should return the firstname. Your data array does not have any firstname property. You need to use forEach method to loop through the items and store the values in an array and return the array.

Kindly use the methods below to retrieve the value in an array format.

// Get all the firstnames in an array

function getFirstName(){

var firstname = [];

data.forEach(function(item){

firstname.push(item.firstName);

});

return firstname;

}

-----------------------------------------------------------------------------------------

// To Set Firstname, we need to pass the unique identifier, which is ID in this case.

function setFirstName(id, value){

data.forEach(function(item){

if(item.id === id){

item.firstName = value;

console.log(item.firstName);

}

});

}

---------------------------------------------------------------------------------

// Get all the lastnames in an array

function getLastName(){

var lastname = [];

data.forEach(function(item){

lastname.push(item.lastName);

});

return lastname;

}

--------------------------------------------------------------------------------------------------------------

// To Set Lastname, we need to pass the unique identifier, which is ID in this case.

function setLastName(id, value){

data.forEach(function(item){

if(item.id === id){

item.lastName = value;

}

});

}

----------------------------------------------------------------------------------------------------------

// Get all the lastnames in an array based on firstname

function getLastName(value){

var lastname = [];

data.forEach(function(item){

if(item.firstName === value)

lastname.push(item.lastName);

});

return lastname;

}