Function isDenseArray

isDenseArray(x: unknown): x is unknown[]
Determine whether a value is a "dense" JavaScript array.

A dense array, for the purposes of this function, is an array that:
- is actually an array (Array.isArray equivalent), and
- has exactly as many own enumerable keys as its length property.
In practice this means:
- Arrays with "holes" (e.g. created with new Array(n) or by leaving indices unset) are not dense.
- Arrays with additional enumerable own properties (e.g. arr.foo = 1) are not dense.
- Elements explicitly set to undefined still count as entries and do not make the array sparse.
Parameters
- x: unknown
  The value to test.
Returns x is unknown[]
true if x is an array and the number of its own enumerable keys equals its length; otherwise false.
Example
```
// true: empty array has 0 keys and length 0
isDenseArray([]); // true

// true: element explicitly set (even if undefined) counts as an entry
isDenseArray([undefined]); // true

// false: "hole" at index 0 -> keys.length (0) !== length (1)
isDenseArray(new Array(1)); // false

// false: extra enumerable property increases keys.length beyond length
const a = [1];
a.foo = 'bar';
isDenseArray(a); // false
```
Since
1.1
- Defined in builtins/array.ts:546