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The problem is that the fill function is filling the array with references to the same empty array[1], and therefore modifying that array will affect every entry because all of them are actually th...
Answer
#1: Initial revision
by
Moshi
·
2022-03-11T05:32:42Z (over 2 years ago)
The problem is that the `fill` function is filling the array with *references* to the *same* empty array[^1], and therefore modifying that array will affect every entry because all of them are actually the same entry.
To get around this, you need to explicitly create a new array for each index, for instance by using a for loop
```javascript
const arrays = [];
for (let i = 0; i < 3; i++) {
arrays.push([]);
}
arrays[0].push('foo');
console.log(arrays); // [ [ 'foo' ], [], [] ]
```
[^1]: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/fill#description