const isNumber = v => (typeof v === 'number' || (typeof v === 'string' && v.trim() !== ''))  ? !Number.isNaN(Number(v)) : false;

// isNumber('') => false
// isNumber(' ') => false
// isNumber('\t') => false
// isNumber('$4') => false
// isNumber('abc') => false
// isNumber('4e') => false
// isNumber(true) => false

// isNumber('4e1') => true
// isNumber('   4 ') => true
// isNumber(4) => true
// isNumber('0') => true
// isNumber(0) => true
// isNumber(-0) => true