## The challenge#

Write a function that when given a number >= 0, returns an Array of ascending length subarrays.

``````pyramid(0) => [ ]
pyramid(1) => [ [1] ]
pyramid(2) => [ [1], [1, 1] ]
pyramid(3) => [ [1], [1, 1], [1, 1, 1] ]
``````

Note: the subarrays should be filled with `1`s

## The solution in Javascript#

Option 1:

``````function pyramid(n) {
const res = [];
for(let i = 0; i < n; i++){
res.push([...Array(i+1)].fill(1))
}
return res;
}
``````

Option 2:

``````function pyramid(n) {
return Array(n).fill().map((e,i)=>Array(i+1).fill(1))
}
``````

Option 3:

``````const pyramid = n => Array(n).fill(1).map((x, i) => Array(i + 1).fill(1))
``````

## Test cases to validate our solution#

``````describe('basic tests', () => {
it("Testing for 0", () => assert.deepEqual(pyramid(0), []));
it("Testing for 1", () => assert.deepEqual(pyramid(1), [[1]]));
it("Testing for 2", () => assert.deepEqual(pyramid(2), [[1], [1, 1]]));
it("Testing for 3", () => assert.deepEqual(pyramid(3), [[1], [1, 1], [1, 1, 1]]));
});
``````