Array map function doesn't change elements

Question

In JavaScript, I have an array, which is

array = [true, false]

In some cases, I am trying to initialize this array

array.map(item => {
   item = false
})

After running the above code, the array is not changed, it is still [true, false], so is .map not reliable sometimes?

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ONE MORE QUESTION: After running my below code, the array is changed. Why does it work in this case?

let array = [{id:1, checked: false}, {id:2, checked:true}]
array.map(item => {
    item.checked = true
})

array becomes [{id:1, checked: true}, {id:2, checked:true}]

Answer 1

JavaScript Array map() Method

*)creates a new array with the results of calling a function for every array element and it calls the provided function once for each element in an array, in order.

Note: map() Method does not execute the function for array elements without values and it does not change the original array.

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