Week 4: Responsive Web Design Coursera Quiz Answers

Quiz 1: JavaScript arrays

Q1. Why are arrays useful?

• They can store very long pieces of text
• They can store lots of individual bits of data

Q2. Which of these is a correctly defined array?

• 1 [‘one’, 2, 3.0]
• 1 {‘one’, ‘two’, ‘three’}

Q3. What is the first element of an array called “a”?

• 1 a[0]
• 1

Quiz 2: Storing objects in arrays and displaying them with a template

Q1. To use a template with an array you need to:

• Create lots of templates, one for each template in an array.
• Use a single template but instantiate it separately with each item in the array.
• Use a single template and instantiate it once with the whole array

Q2. Did you spot the error in my slides? It was with this code.

12345678

• The last template expression should be {{#each}} not {{/each}}
• The div is not closed

Q3. Everything inside the {{#each}} {{/each}} expression is

• Repeated once for each element in the array
• Rendered a single time but with all the data in the array

Quiz 3: Dynamically displaying single images from an array

Q1. How do you access individual elements of an array?

• By number
• By name

Q2. What does {{@index}} do?

• Get a member variable called index
• Get the number of the current item in the array

Q3. What is data-id?

• The identification number of an element of a data array
• A special “data” attribute that allows us to add extra data to an HTML tag

Quiz 4: Implementing a search function

Q1. Why do keypress events represent keyboard keys as numbers and not letters?

• You can’t represent a letter directly on a computer
• Some keyboard keys can’t be represented as letters

Q2. Why do you need to pass a function to filter an array?

• The function takes an individual element of the array and figures out whether it should be kept or not
• The function steps through every element of the array in turn

Q3. Filter changes your array so you need to save a backup

• TRUE
• FALSE

Quiz 5: Data structure for a complete image gallery

Q1. You cannot have an array as a member variable of an object

• TRUE
• FALSE

Q2. You should always represent a photo album as just an array, not an object, because it is just a bunch of photos.

• TRUE
• FALSE

Q3. What data type did I use to represent the name of the photo album?

• An array
• An object
• A string (text)

Quiz 6: Writing the templates for the gallery

Q1. To a hierarchical data structure, like a photo gallery that contains many albums, each of which contains many photos, …

• You must use a different template for each level: one for albums and one for photos
• You can include both levels (albums and photos) in the same template

Q2. What does {{photos.length}} do?

• Renders the “length” member variable of the array “photos”
• Takes two member variables “photos” and “length and joins them together with a dot.

Q3. What does {{#if @first}} do?

• Gets the first element of the current array, if there is one
• Only renders the following template code if the current element is the first one in the array

Quiz 7: Building a full gallery app summary quiz

Q1. What is an array?

• A JavaScript data structure that can store many items and can access them by a number
• A JavaScript data structure that can store many items and can access them by a name
• A template where template expressions access data items by a number
• A template where template expressions access data items by a name

Q2. If you were building a social media site, which of the following would you represent as an array? (select all that apply)

• A person’s name
• A person’s friends list
• A person’s timeline
• A person’s profile

Q3. What is wrong with this array definition?

1var myArray = [“one”, 2, 3.0, [4, 5, “six”];

• It should have curly brackets {} instead of square brackets []
• It has the wrong number of commas (,)
• It has the wrong number of close brackets (])
• You cannot have an array inside another array

Q4. What does this code do?

1$(“#myButton”).click();

• Changes which function is called when the element with id “myButton” is clicked
• Stops any function being called when the element with id “myButton” is clicked
• Calls the function that would normally be called when the element with id “myButton” is clicked
• Changes the style of the element with id “myButton” to look like it does when it is clicked.

Q5. What does the template expression {{#each length}} do?

• Show the member variable “length” of the object “each”
• Show the number of items in the array “each”
• Repeat the following code for all items in the array “length”
• Show the member variable “each” followed by the member variable “length”

Q6. What is wrong with this template definition?

123

{{#each things}}

• {{name}}

• There is an expression {{/each}} missing
• the
  • Instead of {{name}} it should be {{things.name}}
  • Instead of {{#each things}} it should be {{#each}} {{things}}

    Q7. Which template will correctly display all of this data?

    123456789 var mydata = {name : "me",pets : [ {type : "cat",favouritebit : "whiskers"},{type : "dog",favouritebit : "ears"}]}

  • 1234

    {{name}}

    {{pets}}

  • 1234567
    {{#each pets}}

    {{name}}

    {{type}}

    {{favouritebit}}

    {{/each}}

  • 1234567

    {{name}}

    {{pets[0].type}}

    {{pets[0].favouritebit}}

    {{pets[1].type}}

    {{pets[1].favouritebit}}

  • 1234567
    {{name}}

    {{#each pets}}

    {{type}}

    {{favouritebit}}

    {{/each}}

    Q8. When you instantiate this template with an object in which “pets” is an array with many members, which HTML tags only appear once in the final output?

    12345678

    About me

    {{name}}

    {{#each pets}}

    {{type}}

    {{favouritebit}}

    {{/each}}

    (select all that apply)

  • 1

  • 1

  • 1

  • 1


    Q9. What HTML does this template produce when you instantiate it with the data below?

    15

    }]}

  • 123456

    The nations favorite short stories about Aardvarks

    George the killer Aardvark

    Clarice Davies

    Aardvarks of the Carribean

    David Clarence