If I run this code then it console 4 at 5 time, can anyone explain why it is happening ?
let number = 1;
for (var i=0; i<5; i++){
number=i;
setTimeout(()=>{
console.log(number)
},1000)
}
Also if I modify this to as below then output is 5 times 5 ?
for (var i=0; i<5; i++){
setTimeout(()=>{
console.log(i)
},1000)
}
And why it prints 0 to 4 when we use let like
for (let i=0; i<5; i++){
setTimeout(()=>{
console.log(i)
},1000)
}
Its a typical use case of var being functional scope ,every iteration of for loop shares the same value of var (doesn't creates a new scope as var being functional scope) which is kind of global in here
so when the last condition arrives i<5 i is already has become 4 ,and it is shared by every callback of setTimeout so they all prints 4 ,4 times
But in case of let a new scope is formed in every iteration ,as let being a block scope (for loop has a block scope)