demo code as below

let bool: boolean = false;

[1, 2, 3, 4].forEach(i => {
    // do something ...
    if(i === 2){
      bool = true;
    }
})

if (bool === true) {
    console.log('this is test code')
}

This demo code got this error.
This comparison appears to be unintentional because the types ‘false’ and ‘true’ have no overlap.

I can adjust code like this to remove error.

// same code ...

if (bool) {
    console.log('this is test code')
}

but I wanna know the bool variable in if statement is true instead 1 or something else.
how can I do ?