JavaScript Inner-Array

Question

Is it good practice to create a JavaScript array inside another array? Example: I would create an array, "array1", which would contain objects of "array2" and "array3".

Example Code:

var array1 = [];
var array2 = []
array1.push(array2);

The reason I ask this question, is that with a multidimensional array, it seems hard to get the length of all dimensions, however, with this "inner-array," you could get the dimensions quite easily:

array1[0].length

Answer 1

Note that generally it is called "jagged array" (array of arrays) which is not necessary represent rectangular matrix (usually multidimensional arrays that have same number of elements on each level).

JavaScript does not support what usually considered "multidimensional arrays" unlike some other languages where you can do something like matrix = new int[10,20]. So this is the only way to create "multidimensional array" in JavaScript. This post How to initialize a jagged array in JavaScript? may give you other way to initialize the array.

If using it for matrix manipulation code be careful when adding inner arrays: usually code would expect rectangular shape(like nested for loops) and may fail if some inner arrays have wrong dimensions.

Answer 2

Is it good practice to create a JavaScript array inside another array?

The elements contained in an array can be everything, even other arrays. So there's nothing bad in doing that.

The reason I ask this question, is that with a multidimensional array, it seems hard to get the length of all dimensions, however, with this "inner-array," you could get the dimensions quite easily

Your "inner-array" is, in fact, a multidimensional array.