Pretty print a matrix in ES6

matprint.js

"use strict"

function matprint(mat) {
    let shape = [mat.length, mat[0].length];
    function col(mat, i) {
        return mat.map(row => row[i]);
    }
    let colMaxes = [];
    for (let i = 0; i < shape[1]; i++) {
        colMaxes.push(Math.max.apply(null, col(mat, i).map(n => n.toString().length)));
    }

    mat.forEach(row => {
        console.log.apply(null, row.map((val, j) => {
            return new Array(colMaxes[j]-val.toString().length+1).join(" ") + val.toString() + "  ";
        }));
    });
}

// Try it!
let a = [[1,2,3],[4,5555555555555555555555,1],[0.000000000006, 7, 8]];

matprint(a)

/*
    1                       2   3  
    4   5.555555555555556e+21   1  
6e-12                       7   8  
*/