var obj = {
a: 2,
}
var a = 3;
const func = () => {
console.log(this.a);
}
function test() {
setTimeout(func, 100);
}
function test2() {
setTimeout(() => {
console.log(this.a);
}, 100);
}
test.call(obj); //3
test2.call(obj); //2
It seemed that the test and test2 are the same, but the returned result is different, what's the problem with 'this'?
with test arrow function, this will refer to the window object, and as var a = 3, the a will be assigned as a property to the window, it will be like
window.a
But in test2 this will refer to the obj object.