07. NxN Matrix

function solve (num) {

    function NxNMatrix() {
        let print = '';
        for (let i = 0; i < num; i++) {
            for (let j = 0; j < num; j++) {
                print += num + ' ';
            }
            print += '\n';
        }
        return print;
    }
    console.log(NxNMatrix());
}

Или :

function solve (num) {

    for (let i = 0; i < num; i++) {
        console.log(`${num} `.repeat(num));
    }
}