How can I remove the EventListener? Attached is a quick example of where it doesn't work. How should it be correct?
function test_function(a='', b='') {
console.log('test_function started. a='+a+', b='+b);
}
document.body.addEventListener('mousemove', ()=>{ test_function('testa', 'testb'); });
document.body.removeEventListener("mousemove", test_function );
test_function is not the event listener function of the event handler.
it is
()=>{ test_function('testa', 'testb')
this whole anonymous function.
In this document.body.removeEventListener("mousemove", test_function ); you are passing reference of test_function to removeEventListener. but the actual function is ()=>{ test_function('testa', 'testb')
In order to use removeEventListener, you can refactor code this way.
function test_function(a='', b='') {
console.log('test_function started. a='+a+', b='+b);
}
const handleMouseMove = () => test_function('testa', 'testb');
document.body.addEventListener('mousemove', handleMouseMove);
document.body.removeEventListener("mousemove", handleMouseMove);
checkout mdn documentation,
https://developer.mozilla.org/en-US/docs/Web/API/EventTarget/removeEventListener