jsinterview

x = y;
x == y;
x === y;

var x = transform(5)(6);

// x = y * z
var x = transform(5)(6); // x === 30

function transform (y) {
    return function (z) {
        return y * z;
    };
}

typeof 'Hello';
typeof Array.prototype.shift;
typeof new Date();
typeof {a:1};
typeof [1, 2, 3];
typeof null;
typeof NaN;

typeof 'Hello';                // 'string'
typeof Array.prototype.shift;  // 'function'
typeof new Date();             // 'object'
typeof {a:1};                  // 'object'
typeof [1, 2, 3];              // 'object'
typeof null;                   // 'object'
typeof NaN;                    // 'number'

// other typeof return values
'undefined'
'boolean'

#!/usr/bin/node

function bar () {
    var a = 'cat';
    if (1) {
        var a = 'bunny';
        b = 'dog';
    }

    console.log(a);
    console.log(b);
}

function bang () {
    console.log(b);
    console.log(a);
}

bar();
bang();

#!/usr/bin/node

bar();
bang();

function bar () {
    let a = 'cat';
    if (1) {
        let a = 'bunny';
        b = 'dog';
    }

    console.log(a);
    console.log(b);
}

function bang () {
    console.log(b);
    console.log(a);
}

function Dog (name) {
    this.name = name;
}
Dog.prototype.speak = function speak () {
    console.log(`Woof. My name is ${this.name}`);
};

var rex = Dog('Rex');

var Dog = function (name) {
    return {
        name,
        speak: function speak () {
            console.log(`Woof. My name is ${name}`);
        }
    };
};

var rex = Dog('Rex');


let a = (100 + 1/2) - 100;
let b = 1/2;

assert(a === b);


let x = (100 + 1/3) - 100;
let y = 1/3;

assert(x === y);

FizzBuzz

Write a function, using JavaScript syntax, that takes an array of integers as its only argument and, for each element, performs the following:

If the number is evenly divisible by 3, print "Fizz"
If the number is evenly divisible by 5, print "Buzz"
If the number is evenly divisible by both 3 and 5, print "FizzBuzz"
If none of the above, print the number.

FizzBuzz

function fizzBuzz (integers) {
    integers.forEach((i) => {
        let output = '';
        if (i % 3 === 0) {
            output += 'Fizz';
        }
        if (i % 5 === 0) {
            output += 'Buzz';
        }
        console.log(output ? output : i);
    });
}

FizzBuzz

#!/usr/bin/env node
'use strict';

fizzbuzz(...process.argv.slice(2));

function fizzbuzz(...numbers) {
    numbers.map(n => parseInt(n, 10)).forEach(num => {
        let output = '';

        if (num % 3 === 0) output += 'fizz';
        if (num % 5 === 0) output += 'buzz';
        if (output === '') output = num;

        console.log(output);
    });
}

Palindrome

Write a function that takes a string as its only argument and returns a Boolean indicating whether or not the word is a palindrome.

Palindrome

// solution using just Array methods
function isPalindrome (str) {
    return str.split('').reverse().join('') === str;
}

// solution using iteration and Array methods
function isPalindrome (str) {
    let chars = str.split('');
    while (chars.length > 1) {
        if (chars.shift() !== chars.pop()) {
            return false;
        }
    }
    return true;
}