Why Does `map` Seem to Fail on Arrays Created with `new Array(count)`?

Array Creation and the Apparent Failure of map

In certain browsers, creating an array via new Array(count) and attempting to apply the map method on it may yield unexpected results. It's important to understand the mechanism behind this behavior.

new Array(count) initializes an array with count number of elements, all initialized to undefined. Consequently, even though the array appears to be empty, it actually contains a series of undefined values.

The map method, when applied to an array, creates a new array by applying a given function to each element in the original array. In the example provided, the function simply returns 0.

When invoked on an array initialized with new Array(count), the map method appears to have no effect as it returns an array of undefined values. This is because the map function is applied to the undefined values in the original array, which results in a new array of undefined values.

To resolve this issue, one can initialize the array elements with a specific value, even undefined, using the Array.prototype.fill() method before attempting to apply map.

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