This video explains nicely:

and his code (on the 2nd line is the lambda function):

let x = function(a,b,c){return a+b+c;};
let x = (a,b,c) => a+b+c;
alert(x(2,5,1));

and:

setTimeout(function () {alert("2 seconds passed")}, 2000);
setTimeout(() => alert("2.3 seconds passed"), 2000);

you clearly see by comparison with the regular anonymous function and the lambda one that the last one is more convenient and less code is required 🙂