Another way:
for(var a = [];a.length < 10; a.push([])); // semicolon is mandatory here
Yet another way:
var a = []; while(a.push([]) < 10);
This works because .push()
[docs] (specification) returns the new length of the array.
That said, this is the wrong way of “reducing code”. Create a dedicated function with a meaningful name and use this one. Your code will be much more understandable:
function get2DArray(size) {
size = size > 0 ? size : 0;
var arr = [];
while(size--) {
arr.push([]);
}
return arr;
}
var a = get2DArray(9);
Code is read much more often than written.