Q:

Quickest/most elegant way to verify a 2D array has same length per row?

Let's say I have a 2D array:
const matrixRegular = [
    ['a', 'b', 'c'],
    ['e', 'f', 'g'],
];

Let's say I want to verify that every row in this matrix has the same length, so the example above is a valid matrix, but the example below is not:
const matrixIrregular = [
    ['a', 'b', 'c'],
    ['e', 'f']
];

What's a clean/elegant way of doing it? This is the one-liner I have:
const isRegularMatrix = matrix => new Set(data.map(row => row.length)).size === 1

Convert the matrix to an array of just row length, then use Set to ensure every element is a duplicate (same length), hence it comes out with size 1.

A:

You can use every() and compare length of each array with the length of the first.
const isRegularMatrix = matrix => matrix.every(x => x.length === matrix[0].length)

