insafmechergui / closures

Closures

Closure exercises

1. Write a function, nonsense that takes an input string. This function contains another function, blab which alerts string and is immediately called inside the function nonsense. blab should look like this inside of the nonsense function:

    var blab = function(){
      alert(string);
    };

2. In your function, nonsense, change the immediate call to a setTimeout so that the call to blab comes after 2 seconds. The blab function itself should stay the same as before.

3. Now, instead of calling blab inside of nonsense, return blab (without invoking it). Call nonsense with some string and store the returned value (the blab function) in a variable called blabLater. Call nonsense again with a different string and store the returned value in a variable called blabAgainLater.

4. Inspect blabLater and blabAgainLater in your console. Call them (they are functions!) and see what happens!

5. Write a function with a closure. The first function should only take one argument, someone's first name, and the inner function should take one more argument, someone's last name. The inner function should console.log both the first name and the last name.

   var lastNameTrier = function(firstName){
      //does stuff
   
       var innerFunction = function() {
           //does stuff
       };
       //maybe returns something here
   };
   var firstNameFarmer = lastNameTrier('Farmer'); //logs nothing
   firstNameFarmer('Brown'); //logs 'Farmer Brown'

   This function is useful in case you want to try on different last names. For example, I could use firstName again with another last name:

   firstNameFarmer('Jane'); //logs 'Farmer Jane'
   firstNameFarmer('Lynne'); //logs 'Farmer Lynne'

6. Create a storyWriter function that returns an object with two methods. One method, addWords adds a word to your story and returns the story while the other one, erase, resets the story back to an empty string. Here is an implementation:

   var farmLoveStory = storyWriter();
   farmLoveStory.addWords('There was once a lonely cow.'); // 'There was once a lonely cow.'
   farmLoveStory.addWords('It saw a friendly face.'); //'There was once a lonely cow. It saw a friendly face.'
   
   var storyOfMyLife = storyWriter();
   storyOfMyLife.addWords('My code broke.'); // 'My code broke.'
   storyOfMyLife.addWords('I ate some ice cream.'); //'My code broke. I ate some ice cream.'
   storyOfMyLife.erase(); // ''