How to “build” string form one property of an object array?

I have an array that contains objects, like this:

"exams": [    
    {
      "id": "62b30836e941368db5d0e531",
      "name": "Basic",
      "price": 100
    },
    {
      "id": "62b30836e941368db5d0e532",
      "name": "Full",
      "price": 200
    }
]

I need pick only the name property from every object, and build a string, where the elements are “separated” with comma. Like this:

"Basic,Full"

I tried the following, but the method built every whole object into the string:

var e = exams.join(",");

Answer

Before using the .join() to create a string, you should map the values you want from the array of objects. Like this:

exams.map(exam => exam.name)

This should return something like: ['Basic', 'Full'].

Then you do the join.

You could do all in one line (also avoid var, use const instead):

const e = exams.map(exam => exam.name).join(',')