Though I am aware of "Global scope, function scope, block scope" in JavaScript. I got stuck in this code block.
I simplified the logics of the code as follows. What I expected is, the console.log(a, b, c) in execute function would be a = 3, b = 6, c = 9.
But what I actually got is a = 0, b = 0, c = 0. What's going wrong and how to fix this? Thanks
(function() {
let a,b,c;
let conditions = [-1, 1, 2, 3 ];
const execute = () => {
for (let i=0; i<conditions.length; i++) {
if (conditions[i] < 0) {
a = 0;
b = 0;
c = 0;
} else if (conditions[i] > 0) {
update(a, b, c);
}
}
console.log(a,b,c);
}
const update = (a, b, c) => {
a = a + 1;
b = b + 2;
c = c + 3;
}
execute();
})()
Here, by not declaring params to update(), the assignments are made to the variables in the parent scope.
(function() {
let a,b,c;
let conditions = [-1, 1, 2, 3 ];
const execute = () => {
for (let i=0; i<conditions.length; i++) {
if (conditions[i] < 0) {
a = 0;
b = 0;
c = 0;
} else if (conditions[i] > 0) {
update(); // edit
}
}
console.log(a,b,c);
}
const update = () => {
a = a + 1;
b = b + 2;
c = c + 3;
}
execute();
})()