how can I print a list of variables within a function using console.log in javascript node.js

Question

function listacursos(curso1,curso2,curso3){
    let curso1=[{
        Ide: 154532,
        nombre:'marketing digital basico',
        duracion: '15 dias',
        valor: 100000,

    }];
        let curso2=[{
        Ide: 154533,
        nombre:'diseño grafico basico',
        duracion: '30 dias',
        valor: 200000,
    }];
        let curso2={
        Ide: 154534,
        nombre:'animacion digital',
        duracion:'35 dias',
        valor: 180000,
    };  
}
    setInterval(function(listacursos){
        console.log('el nombre del curso es: '+curso2.nombre)
     },3000);**strong text**

I am trying to create a program that lists me every variable course in the function "listacursos" but I see error as if the variable was not being declared, I have tried everything because it has to show a message with the information of each course in a period of time of 2 seconds, I know how to do the time delay but I can not make the impression with the console.log.

This is the error that the cmd shows me enter image description here

Derek Brown · Accepted Answer · 2019-03-16 04:57:04Z

1

The reason you can't access the variables inside of your listacursos function is because of variable scoping.

In Javascript there are two types of variables; variables declared inside of functions are locally-scoped meaning they can only be accessed within that function:

function example(){
   let foo = "test1";
   console.log(foo); // Fine!
}
console.log(foo); // Raises an Error

And globally-scoped, variables declared outside of a function, which can be accessed everywhere:

const foo = "test1";
function example(){
   console.log(foo); // Fine!
}
console.log(foo); // Fine!

This is a somewhat simplified explanation, but there is a more in-depth explanation here.

answered Mar 16, 2019 at 4:57

Derek Brown

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Comments

Marin Mouscadet · Accepted Answer · 2019-03-16 09:06:06Z

The answer by Derek Brown is correct by I will add more precision to your code

function listacursos(curso1,curso2,curso3){
    let curso1=[{
        Ide: 154532,
        nombre:'marketing digital basico',
        duracion: '15 dias',
        valor: 100000,

    }];
        let curso2=[{
        Ide: 154533,
        nombre:'diseño grafico basico',
        duracion: '30 dias',
        valor: 200000,
    }];
        let curso2={ //You already declare a "curso2" variable 
        Ide: 154534,
        nombre:'animacion digital',
        duracion:'35 dias',
        valor: 180000,
    };  
}
    setInterval(function(listacursos){ // Your function 'listacurso' doesn't return anything, so you are just executing it.
        console.log('el nombre del curso es: '+curso2.nombre)
     },3000);

In order to make it work I would suggest that you do something like

    function listacursos(){
        let obj = {};
        let curso1=[{
        Ide: 154532,
        nombre:'marketing digital basico',
        duracion: '15 dias',
        valor: 100000,

    }];
        let curso2=[{
        Ide: 154533,
        nombre:'diseño grafico basico',
        duracion: '30 dias',
        valor: 200000,
    }];
        let curso3={
        Ide: 154534,
        nombre:'animacion digital',
        duracion:'35 dias',
        valor: 180000,
    };
    obj.curso1 = curso1;
    obj.curso2 = curso2;
    obj.curso3 = curso3;
    return obj;
}
    setInterval(function(){
        let courso = listacursos();
        console.log('el nombre del curso es: ', courso.curso2[0].nombre)
     },3000);

Which means that you store every "curso" in an "obj" a JS JSON to be more precise and you return it. Then you create a variable to store that JSON, the "curso" variable.

As "curso2" is actually an array you have to add "[0]" in order to read the JSON inside.

You can fond more about JSON here : https://www.w3schools.com/js/js_json.asp

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