-
-
Save jasonwyatt/577977 to your computer and use it in GitHub Desktop.
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
// 1: how could you rewrite the following to make it shorter? | |
bar['doSomething' + (foo ? '' : 'Else')](el); | |
// 2: what is the faulty logic in the following code? | |
// It will always print "world" to the console because foo is undefined in the | |
// anonymous function's closure at the time of the shortcut attempt. | |
// 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(); | |
Thinger.prototype.log = function(){ | |
// summary: | |
// Logs the 'bar' attribute of any Thinger. | |
console.log(this.bar); | |
} | |
Thinger.prototype.isBarChanged = (function(original){ | |
// summary: | |
// Determines if the 'bar' attribute was changed from the default 'baz' | |
// value. | |
// returns: | |
// Boolean, true if 'bar' has been changed to something other than 'baz'. | |
// False otherwise. | |
return function(){ | |
returns this.bar === original; | |
}; | |
})(Thinger.prototype.bar); | |
foo.bar = "moo"; // modifies only foo's 'bar' attribute, not bim's. | |
Thinger.prototype.bar = "oink"; // modifies not only foo and bim's 'bar' attr, | |
// but any previously and yet-to-be created | |
// Thingers' 'bar' attributes as well. | |
// 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() | |
}; | |
var attrs = []; | |
for(var i in myObjects){ | |
if(myObjects.hasOwnProperty(i)){ | |
myObjects[i].destroy(); | |
attrs.push(i); | |
} | |
} | |
for(var i = 0, len = attrs.length; i < len; i++){ | |
delete myObjects[attrs[i]]; | |
} | |
// 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' ]; | |
var yourArray = $.map(myArray, function(val){ | |
return [val, val, val].join(' '); | |
}); | |
// 6: how could you improve the following code? | |
$(function() { | |
var $foobar = $('#bar'); // because IDs have to be unique, we can simplify the selector. | |
$foobar.css({ | |
'color': 'red', | |
'border': '1px solid blue' | |
}) | |
.text('new text!') | |
.click(function() { | |
$(this).attr('title', 'new title') | |
.width('100px'); | |
}); | |
// like to keep this separate and not-chained to separate "setup" from triggering. | |
$foobar.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 | |
} | |
})(); | |
/* | |
This code is not built with the "A" of "AJAX" in mind - asynchronous execution. If the load callback isn't called immediately (the http response comes back immediately), foo will be undefined in the block underneath... I would introduce a timeout to wait until foo is set... JUST KIDDING! You could fix this in a number of ways: | |
1) Put the "important code" inside of the load callback. | |
2) Subscribe to a pubsub event channel before the dojo.xhrGet with the important code. Then inside the load callback - trigger an event on that channel when foo is received. | |
3) Store the configuration object for dojo.xhrGet outside of the function call in an object literal and do a dojo.connect on the 'load' function with the important code before passing the literal to xhrGet. | |
The option you should select is dependent on the situation. | |
*/ | |
// 8: how could you rewrite the following code to make it shorter? | |
(function(d, $){ | |
d.forEach(['foo', 'bar', 'baz', 'bop'], function (classname){ | |
$('li.'+classname+' a').attr('title', 'i am '+classname); | |
}); | |
})(dojo, dojo.query); | |
// 9: how would you improve the following code? | |
var thingerPrefix = '<p><span class="thinger">i am thinger ', | |
thingerSuffix = '</span></p>', | |
gizmoPrefix = '<p><span class="gizmo">i am gizmo ', | |
gizmoSuffix = '</span></p>', | |
thingerStrings = [], | |
gizmoStrings = []; | |
for (i = 0; i <= 100; i++) { | |
thingerStrings = thingerStrings.concat([thingerPrefix, i, thingerSuffix]); | |
gizmoStrings = gizmoStrings.concat([gizmoPrefix, i, gizmoSuffix]); | |
} | |
$('#thinger').append(thingerStrings.join('')); | |
$('#gizmo').append(thingerStrings.join('')); | |
// 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; | |
} | |
// All values entered could possibly be strings (most likely the input value, | |
// but possibly by mistake in application code: the others) in which case the | |
// returned value would be a bunch of concatenated strings (not a real value | |
// that we're looking for) | |
// 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' | |
} | |
]; | |
function comprehend(arr){ | |
// summary: | |
// Iterates over the array that is passed in, and returns an array | |
// containing strings which describe the items in the array by name and | |
// a list of their extras - if available. | |
// returns: | |
// Comprehended array. | |
var result = []; | |
for(var i = 0, len = arr.length; i < len; i++){ | |
var item = arr[i].name; | |
if(arr[i].extras && arr[i].extras.length > 0){ | |
item = item + ' (' + arr[i].extras.join(', ') + ')'; | |
} | |
result.push(item); | |
} | |
return result; | |
} | |
// BONUS: write code such that the following alerts "Hello World" | |
say('Hello')('World'); | |
function say(str1){ | |
return function(str2){ | |
alert(str1 + ' ' + str2); | |
}; | |
} | |
// 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(', ')); | |
// If the current day is less than 5 days from the end of the month, we will end | |
// up with an incorrect month value for those days that extend into the next month. | |
// Instead of this code, I would build date objects for each of the next 5 days | |
// (and including today) and construct my strings from those objects. The date | |
// class will automatically roll over to the next month if you have date values | |
// that are greater than the specified month's maximum number of days. |
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment