What is this way of a JavaScript function declaration called? (var) => {}

Question

upon reading the latest NodeJS docs I encountered a new way of declaring a function:

fs.unlink('/tmp/hello', (err) => {
  if (err) throw err;
  console.log('successfully deleted /tmp/hello');
});

Source: https://nodejs.org/api/fs.html#fs_file_system

Now I want to know how this (var) => { <functon-content> } type declaration is called, so that I can research more on it.

I have not yet found anything online regarding this topic. :(

ECMA6 function declaration : https://developer.mozilla.org/en/docs/Web/JavaScript/Reference/Functions/Arrow_functions. Please research around before posting such questions. — NiRUS, Jan 15 '16 at 18:03

score 4 · Accepted Answer · answered Jan 15 '16 at 18:03

It's a feature of the ECMAScript 6 called Arrow Function: https://developer.mozilla.org/en/docs/Web/JavaScript/Reference/Functions/Arrow_functions

An arrow function expression (also known as fat arrow function) has a shorter syntax compared to function expressions and lexically binds the this value (does not bind its own this, arguments, super, or new.target). Arrow functions are always anonymous.

What is this way of a JavaScript function declaration called? (var) => {}

1 Answers1