How to empty an array in JavaScript?

I am using ArrayList as my array,

let ArrayList   =  ['a','b','c','d','e','f'];

I am confused in between Method 1 and Method 2 because in both case I Referenced ArrayList by another you can also check logs over this link https://jsfiddle.net/mnjsnj/u1fms8wx/2/

Method 1

let Method1 = ArrayList;  // Referenced arrayList by another variable 
ArrayList= []; // Empty the array 
console.log(Method1); // Output ['a','b','c','d','e','f']

Method 2

let Method2 = ArrayList;  // Referenced arrayList by another variable 
ArrayList.length = 0; // Empty the array by setting length to 0
console.log(Method2 ); // Output []