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screening.js
JavaScript
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// 1: how could you rewrite the following to make it shorter?
if (foo) {
bar.doSomething(el);
} else {
bar.doSomethingElse(el);
}
 
 
// not sure I would though.. sometimes the above is more readable than the below
(foo) ? bar.doSomething(el) : bar.doSomethingElse(el);
 
 
// 2: what is the faulty logic in the following code?
var foo = 'hello';
 
(function() {
var foo = foo || 'world';
console.log(foo);
})();
 
// redeclaring the variable inside the closure makes it loose its value
 
 
// 3: given the following code, how would you override the value of the bar
// property for the variable foo without affecting the value of the bar
// property for the variable bim? how would you affect the value of the bar
// property for both foo and bim? how would you add a method to foo and bim to
// console.log the value of each object's bar property? how would you tell if
// the object's bar property had been overridden for the particular object?
var Thinger = function() {
return this;
};
 
Thinger.prototype = {
bar : 'baz'
};
 
var foo = new Thinger(),
bim = new Thinger();
 
// how would you override the value of the bar
// property for the variable foo without affecting the value of the bar
// property for the variable bim?
foo.bar = 'sum';
 
// how would you affect the value of the bar
// property for both foo and bim?
Thinger.prototype.bar = 'sum';
 
// how would you add a method to foo and bim to
// console.log the value of each object's bar property?
Thinger.prototype.getBar = function() { console.log(this.bar); };
 
// how would you tell if
// the object's bar property had been overridden for the particular object?
foo.hasOwnProperty('bar');
 
 
 
// 4: given the following code, and assuming that each defined object has a
// 'destroy' method, how would you destroy all of the objects contained in the
// myObjects object?
var myObjects = {
thinger : new myApp.Thinger(),
gizmo : new myApp.Gizmo(),
widget : new myApp.Widget()
};
 
for(index in myObjects) {
myObjects[index].destroy();
}
 
 
 
// 5: given the following array, create an array that contains the contents of
// each array item repeated three times, with a space between each item. so,
// for example, if an array item is 'foo' then the new array should contain an
// array item 'foo foo foo'. (you can assume the library of your choice is
// available)
var myArray = [ 'foo', 'bar', 'baz' ];
 
myArray.map(function(item) {
return item + ' ' + item + ' ' + item;
});
 
// [item, item, item].join(' ') would be an alternative
// we could also use map instead of forEach if overwriting myArray
// is not an issue
 
 
// 6: how could you improve the following code?
$(document).ready(function() {
$('.foo #bar').css('color', 'red');
$('.foo #bar').css('border', '1px solid blue');
$('.foo #bar').text('new text!');
$('.foo #bar').click(function() {
$(this).attr('title', 'new title');
$(this).width('100px');
});
$('.foo #bar').click();
});
 
// i'd prefer css classes over setting properties directly, i guess
$(function() {
var bar = $('.foo #bar');
bar.
css({
color: 'red',
border: '1px solid blue'
}).
text('new text!').
click(function() {
bar.
attr('title', 'new title').
width('100px');
}).
click();
});
 
 
 
 
// 7: what issues do you see with the following code? how would you fix it?
(function() {
var foo;
 
dojo.xhrGet({
url : 'foo.php',
load : function(resp) {
foo = resp.foo;
}
});
 
if (foo) {
// run this important code
}
})();
 
// the loading is asynchronous, whereas the if is evaluated synchronously,
// so foo is set "too late". so either we run the important code within the
// load function by putting it in a function and calling that from within
// the load function (maybe we need to bind it first), or we use events for this.
(function() {
var div = $('div');
 
dojo.xhrGet({
url : 'foo.php',
load : function(resp) {
div.trigger('fooLoaded', [resp.foo]);
}
});
 
div.bind('fooLoaded', function(evt, foo) {
if (foo) {
// run this important code
}
});
})();
 
 
 
 
// 8: how could you rewrite the following code to make it shorter?
(function(d, $){
$('li.foo a').attr('title', 'i am foo');
$('li.bar a').attr('title', 'i am bar');
$('li.baz a').attr('title', 'i am baz');
$('li.bop a').attr('title', 'i am bop');
})(dojo, dojo.query);
 
(function(d, $){
['foo', 'bar', 'baz', 'bop'].forEach(function(item) {
$('li.' + item + ' a').attr('title', 'i am ' + item);
});
})(dojo, dojo.query);
 
 
 
 
// 9: how would you improve the following code?
for (i = 0; i <= 100; i++) {
$('#thinger').append('<p><span class="thinger">i am thinger ' + i + '</span></p>');
$('#gizmo').append('<p><span class="gizmo">i am gizmo ' + i + '</span></p>');
}
 
$(function() {
var objects = {
thinger: $('#thinger'),
gizmo: $('#gizmo')
};
 
for(var i = 0; i <= 100; i++) {
for(key in objects) {
objects[key].append('<p><span class="' + key + '">i am ' + key + ' ' + i + '</span></p>');
}
}
});
 
 
 
// 10: a user enters their desired tip into a text box; the baseTotal, tax,
// and fee values are provided by the application. what are some potential
// issues with the following function for calculating the total?
function calculateTotal(baseTotal, tip, tax, fee) {
return baseTotal + tip + tax + fee;
}
 
// * the tip needs to be converted to a float with parseFloat,
// * if the tip is negative the amount might decrease
 
 
 
 
// 11: given the following data structure, write code that returns an array
// containing the name of each item, followed by a comma-separated list of
// the item's extras, if it has any. e.g.
//
// [ "Salad (Chicken, Steak, Shrimp)", ... ]
//
// (you can assume the library of your choice is available)
var menuItems = [
{
id : 1,
name : 'Salad',
extras : [
'Chicken', 'Steak', 'Shrimp'
]
},
{
id : 2,
name : 'Potato',
extras : [
'Bacon', 'Sour Cream', 'Shrimp'
]
},
{
id : 3,
name : 'Sandwich',
extras : [
'Turkey', 'Bacon'
]
},
{
id : 4,
name : 'Bread'
}
];
 
menuItems.map(function(item) {
var _item = item.name;
if(item.extras) {
_item += ' (' + item.extras.join(', ') + ')'
}
return _item;
});
 
 
 
// BONUS: what is the faulty logic in the following code? how would you fix it?
var date = new Date(),
day = date.getDate(),
month = date.getMonth(),
dates = [];
for (var i = 0; i <= 5; i++) {
dates.push(month + '/' + (day + i));
}
 
console.log('The next five days are ', dates.join(', '));
 
// outputs 6 instead of 5 days, fix:
for (var i = 1; i < 6; i++) {

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