JSFiddle - React, Tailwind, and code Playground

JavaScript

$(function() {

    function noMetakeyPressed(metakeysPressed) {
        for (var k in metakeysPressed) {
            if (metakeysPressed[k]) {
                return false;
            }
        }
        return true;
    }

    var metakeysPressed = {17: false, 18: false};
    
    $('body')
    .bind('keydown', function(event) {
        switch(event.keyCode) {
        case 17: // Ctrl
        case 18: // Alt
            metakeysPressed[event.keyCode] = true;
            break;
        case 66: // B
            if (noMetakeyPressed(metakeysPressed)) {
                alert("B pressed");
            }
            break;
        }
    })
    .bind('keyup', function(event) {
        if(event.keyCode === 17 || event.keyCode == 18) {
            metakeysPressed[event.keyCode] = false;
        }
    });
});