You could use the filter like:
arr = arr.filter(item => item);
Example:
let arr = ['One', 'Two', '', 'Four', '', ''];
arr = arr.filter(item => item);
console.log(arr);
// Result
// ['One', 'Two', 'Four']
Because an empty string evaluates to boolean false.
It works with all falsy values like 0, false, null, undefined, '', etc.
DEMO
If you want to keep some values like number 0 (zero) you could use item !== undefined. This filters only undefined values. Keep in mind to trim your string or check with regex to ensure empty strings without whitespaces.