Built-In Objects

       
        const first = 'this is a string';
        const second = String('this is a string');
        console.log('this is a string'.toUpperCase());
        console.log(String('this is a string').toUpperCase());


        console.group('Primitives vs Objects');
            console.log(first === second);  // true
            console.log(
                typeof first,
                typeof String('this is a string'),
                typeof new String()
            );
        console.groupEnd();

        // Strings
        const sentence = 'this is my sentence';
        console.group('String');
            console.log(first.toUpperCase()); // THIS IS A STRING
            console.log(second.toLowerCase()); // this is a string
            console.log(sentence.startsWith('this is')); // true
            console.log('👾'.repeat(20));
            console.log('look at me goo       '.trim());
        console.groupEnd();

        // Numbers and Math
        console.group('Numbers and Math');
            console.log(1..toString()); // 1
            console.log((1).toString());    // 1
            console.log(Number.isInteger(5));   // true
            console.log(Number.isInteger(5.43));    // false
            console.log((1.562342).toFixed(2))  // 1.56
            console.log(
                Math.random().toFixed(2),
                Math.ceil(1.56),
                Math.floor(6.3)
            )
        console.groupEnd();

        // Arrays
        const myArr = ['max', 'nick', 'holly'];
        console.group('Arrays');
            console.log(myArr.length);  // 3
            console.log(myArr.join('-'));   // max-nick-holly
            console.log(myArr.push('ado'), myArr);  // 4  ["max", "nick", "holly", "ado"]
            console.log(myArr.pop(), myArr);    // ado  ["max", "nick", "holly"]

            myArr.forEach(function(user) {
                console.log(user);
            });

            // Simplified with arrow functions
            myArr.forEach((user) => console.log(user));
        console.groupEnd();