Combine Fullname in ES6

Question

How do you combine firstName, middleName and lastName in ES6? What I do is ${firstName} ${middleName} ${lastName} But the problem there is a space in between if middleName is not there. Middle name is not always present

Answer 1

[firstName, middleName, lastName].filter(Boolean).join(" ")

should work just fine.

Since the empty string is falsy and Boolean(x) will compute the truthiness of x, .filter(Boolean) will drop it.

Answer 2

You can nest and use a ternary

const firstName = "John"
const lastName="Doe"
console.log(
`${firstName} ${typeof middleName !== "undefined" ? `${middleName} ` : ''}${lastName}`
)

Answer 3

You can remove the first space between the first and middle name and handle it in the middle name itself example:

`${firstName}${middleName ? ' ' + middleName : ''} ${lastName}`

Answer 4

You can do so by using javascript template literals:

const firstName = "John";
const lastName="Doe";
const middleName="middle";

const printFullName = (firstName, lastName, middleName) => {
   console.log(
     `${firstName}${middleName ? ` ${middleName}` : ''} ${lastName}`
   )
}

printFullName(firstName, lastName);
printFullName(firstName, lastName, middleName);