is function js code example

Example 1: check if function javascript

variableToCheck instanceof Function

Example 2: define function in javascript

/* Declare function */
function myFunc(param) {
  // Statements 
}

Example 3: javascript functions

function sayHelloTo(to) {
  alert(`Hello ${to}`);
}
sayHelloTo('World from Grepper')

Example 4: isfunction javascript

function isFunction(functionToCheck) {
 return functionToCheck && {}.toString.call(functionToCheck) === '[object Function]';
}