1arr = [];   // set array=[]
2
3//function
4const empty = arr => arr.length = 0;
5//example
6var arr= [1,2,3,4,5];
7empty(arr) // arr=[]

1const myArray1 = []
2// or...
3const myArray2 = new Array()

1var colors=[];
2if(!colors.length){
3	// I am empty
4}else{
5	// I am not empty
6}

1Array.from({length: 500})
2
3// change the length to whatever value you want

1let myArray = [12 , 222 , 1000 ];  
2myArray.length = 0; // myArray will be equal to [].

1// set array
2arr = [1,2,4];
3
4// empty array
5arr = [];