Rediscovering JavaScript: ES6, ES7 & ES8/

...

/

Limitations: No Prototype and new.target Property

Limitations: No Prototype and new.target Property

Learn about the limitations of arrow functions, specifically how they lack the prototype property and the new.target property.

We'll cover the following...

new.target is lexically scoped

Functions may use new.target to determine if they were called as a constructor or as a regular function.

For non-arrow functions

In the following code, we use the new.target property to check how the function was called.

Press + to interact
'use strict';
//START:CODE
const f1 = function() {
  if(new.target) {
    console.log('called as a constructor');    
  }
  else {
    console.log('called as a function');    
  }
};                  
      
new f1();
f1();
//END:CODE

If the function is called as a constructor, new.target refers to the constructor function; otherwise, it’s undefined. The previous code’s output confirms this behavior.

For arrow functions

Generally speaking, arrow functions don’t have the new.target property. This makes sense because arrow functions can’t be invoked as constructors. However, if we reference this property within an arrow function we will not get a “new.target is not ...