mind_quiz.js

// Q1. What is a variable? (Describe in your own words)

// Q2.
var a = 1;
var b = 2;
var x = 3;

function test(x,y) {
  x = 10;
  a = y;

  var b = x + a;

  return b;
}

test(5,6);


// What is:
// * return value of the function?
// * the final value of a:
// * the final value of b:
// * the final value of x:

// Q3. What is a function?

// Q4. What are two different ways of creating a function in JavaScript?

// Q5. What is a closure?

// Q6. What is a callback?

// Q7.
function doit(a, cbk) {
   var x = a + 10;
   return cbk(x) + 3;
}

var res1 = doit(5, n => n + 2);

var p = 100;
function again(x) {
  p += x;
  return p + 2;
}

var res2 = doit(8, again);
var res3 = doit(2, again);


// What is the value of res1:
// * res2:
// * res3:
// * the final value of p:


// Q8. What is a Promise?

// Q9. What is a regular expression?
// * What are two different ways of creating a regular expression?
// * var searchStr = "pizza";
//  	* What is the code to create a regular expression that searches for: any number of "a" characters, the value of searchStr, a space, and then 1 or more "b" characters?


// Q10. var VS let trickery
a = 1;
b = 5;

function abc() {
 a = 5;
 let b = 10;

 var a;
 
 return a;
}

var res = abc();

// * What is the value of `res`: 
// * What is the final value of a:
// * What is the final value of b:

// Q12.
a = 1
b = 5;
function xyz() {
  a = 4;

  for (let a = 10; a < 12; a++) {
    b++;
  }

  return a;
}

var res2 = xyz();

// * What is the value of `res2`:
// * What is the final value of a:
// * What is the final value of b:

// Q1. What is a variable? (Describe in your own words)

A label pointing to a container for data.

// Q2.
var a = 1;
var b = 2;
var x = 3;

function test(x,y) {
b = 10;
a = y;

var b = 5 + 6;

return b;
}

test(5,6);

// What is:
// * return value of the function?
11
// * the final value of a:
6
// * the final value of b:
11
// * the final value of x:
5

// Q3. What is a function?
A block of code defining a series of actions to be executed within its own scope.

// Q4. What are two different ways of creating a function in JavaScript?
function foo(arg){...}

var x = function(arg){...}

// Q5. What is a closure?

A function enclosed within another function that has access to the outer function's variable declarations.

// Q6. What is a callback?
A function defined earlier passed as an argument into a subsequent function to be executed later on.

// Q7.
function doit(a, cbk) {
var x = a + 10;
return cbk(x) + 3;
}

var res1 = doit(5, n => n + 2);

var p = 100;
function again(x) {
p += x;
return p + 2;
}

var res2 = doit(8, again);
var res3 = doit(2, again);

// What is the value of res1:

20

// * res2:

123

// * res3:

117

// * the final value of p:

100

// Q8. What is a Promise?

A stand-in for the outcome of an asynchronous operation.

// Q9. What is a regular expression?

An object that matches a pattern of characters in a string.

// * What are two different ways of creating a regular expression?
let regExp = /target/;
let regExp = new RegExp('target');

// * var searchStr = "pizza";
// * What is the code to create a regular expression that searches for: any number of "a" characters, the value of searchStr, a space, and then 1 or more "b" characters?

var search = new RegExp('/a*/'searchStr'/\s/b+/')
***Totally guessing about the value of searchStr...I couldn't find any documentation on how to search for variables's values. Must be using the wrong search terms.

// Q10. var VS let trickery
a = 1;
b = 5;

function abc() {
a = 5;
let b = 10;

var a;

return a;
}

var res = abc();

// * What is the value of res:

Return value? 5

// * What is the final value of a:

5. I think because even though a is set equal to 5 within the function's scope, the absence of a "var" or "let" means that that assignment applies globally. But I'm not 100% sure.

// * What is the final value of b:
5

// Q12.
a = 1
b = 5;
function xyz() {
a = 4;

for (let a = 10; a < 12; a++) {
b++;
}

return a;
}

var res2 = xyz();

// * What is the value of res2:
4
// * What is the final value of a:
4. "a=4" has global scope even though it is defined within a function.
// * What is the final value of b:
5. The incremented b is not returned. It is erased once the for loop completes.