Inversion of Control (IoC) is usually foundin programming, but it is a general concept. The concept relates to a program’s flow of control.
A program’s flow of control can be thought of as the direction a program executes. The simplest illustration of this is top-to-bottom line-by-line execution of a program.
console.log(1);
console.log(2);
console.log(3);The numbers 1, 2, 3 will be logged into the console in this order. The written program has control of what and when the numbers are shown.
Contrast the above example with:
document.querySelector('.button-1')
.addEventListener('click', function(e) {
console.log(1);
});
document.querySelector('.button-2')
.addEventListener('click', function(e) {
console.log(2);
});This code add event listeners to 2 buttons button-1 and button-2. The program describes what will happen (logging a number), but it has left when to the browser which in turn leaves it to the user of the browser. It is said that the control has been inverted away from the application/program (the code which defines the number logging) to the framework (the browser)
The word “framework” is an abstract and necessary concept when dealing with IoC since it would decide when certain methods shall be called.
To read more, check out Examples of Inversion of Control