console.time("answer time");

alert("Click to continue");

console.timeLog("answer time");

alert("Do a bunch of other stuff…");

console.timeEnd("answer time");

console.time("concatenation");

let output = "";

for (var i = 1; i <= 1e6; i++) {

  output += i;

}

console.timeEnd("concatenation");

console.time();   // Begin timer

// Run code

console.timeEnd();   // End timer and output time

console.time("answer time");

alert("Click to continue");

console.timeLog("answer time");

alert("Do a bunch of other stuff...");

console.timeEnd("answer time");

​

console.time('factorial');

​

const number = 10;

let result = 1;

for (let i = 1; i <= number; i++) {

    result *= i;

    console.timeLog('factorial');

}

​

console.log('factorial result', result);

console.timeEnd('factorial');

const heroes = [

    { name: 'Spiderman', universe: 'Marvel' },

    { name: 'Iron Man', universe: 'Marvel' },

    { name: 'Hulk', universe: 'Marvel' },

    { name: 'Batman', universe: 'DC' },

    { name: 'Superman', universe: 'DC' },

    { name: 'Wonder Woman', universe: 'DC' },

]

​

const marvel = heroes.filter(h => h.universe === 'Marvel');

​

console.table(marvel);

const heroes = [

    {

        name: 'Spiderman',

        firstName: 'Peter',

        lastName: 'Parker',

        city: 'New York City'

    }, {

        name: 'Iron Man',

        firstName: 'Tony',

        lastName: 'Stark',

        city: 'New York City'

    }];

​

console.table(heroes);

let batman = { name: 'Batman' };

// batman.firstName = "Bruce";

// batman.lastName = "Wayne";

console.log(batman);

​

batman = { ...batman, firstName: 'Bruce', lastName: 'Wayne' };

console.log(batman);

let heroes = [

    ['Superman', 'Batman', 'Wonderwoman'],

    ['Spiderman', 'Iron Man', 'Hulk']

]

​

console.log(heroes.flat());