how to remove undefined in array code example

Example 1: remove undefined from array javascript

var data = [42, 21, undefined, 50, 40, undefined, 9];

data = data.filter(function( element ) {
   return element !== undefined;
});

Example 2: js remove undefined from array

const a = [3,,null, false, undefined, 1];

// Remove falsey
a.filter(Boolean);
 
// Remove specific (undefined)
a.filter(e => e !== undefined);