I don't understand how this code works

JavaScript
1 
const names = ["Hole-in-one!", "Eagle", "Birdie", "Par", "Bogey", "Double Bogey", "Go Home!"];

function golfScore(par, strokes) {
  // Only change code below this line
if(strokes == 1){
  return names[0]
}
else if(strokes <= par - 2){
  return names[1]
}
else if(strokes == par-1){
return names[2]
}
else if(strokes == par){
  return names[3]
}
else if(strokes == par + 1){
  return names[4]
}
else if(strokes == par + 2){
  return names[5]
}
else if(strokes >= par + 3){
  return names[6]
}
else{
  return "Change Me";
}
  
  // Only change code above this line
}

golfScore(5, 4);

This is code from the site freecodecamp.org, having reached this example, I don’t understand anything about how it all works, for example the first line if hits == 1, but at the same time in the value function 4 I can’t understand it at all, this is javascript

2

Well, if you hit a golf shot in one shot it means you got a hole-in-one so there’s no need to go any further. In your example you got a birdie Strokes 4 Par is 5 = -1 Birdie

3

I got to this exercise and there’s nothing clear to me here, <= par - 2 in the function it is indicated (5,4) if this is translated then 4 <= “5-2=>”3 that is, and this again is not clear to me

4

A bit of a breakdown

const names = ["Hole-in-one!", "Eagle", "Birdie", "Par", "Bogey", "Double Bogey", "Go Home!"];

Arrays are indexed starting at zero.

// names Array
0 : "Hole-in-one!", 
1 : "Eagle", 
2 : "Birdie", 
3 : "Par", 
4 : "Bogey", 
5 : "Double Bogey", 
6 : "Go Home!"

For example

console.log(names[0]); // "Hole-in-one!"
console.log(names[5]); // "Double Bogey"
console.log(names[9]); // undefined (nothing stored in index position 9)

We have a function called golfScore that takes two arguments, par and strokes.The function will return (output) a string e.g. “Hole-in-one!” or “Go Home!”. The string the function returns depends on the values you pass in for par and strokes.

Commented code

function golfScore(par, strokes) {
  // Note: 'return' will output a value and immediately exit the function at that point.
  
  // if strokes equals 1
  if (strokes === 1) {
    return names[0] // exit with "Hole-in-one!"
  }
  
  // if strokes is smaller or equals par minus 2
  // e.g. golfScore(5, 2) a par of 5 minus 2 is 3, and strokes is 2. 
  // 2 is smaller or equal to 3, 2 <= 3 is true
  else if(strokes <= par - 2) {
    return names[1]; // exit with "Eagle"
  }
  
  // if strokes is equal to par minus 1.
  // e.g. golfScore(4, 3) a par of 4 minus 1 is 3, and strokes is 3.
  // 3 equals 3, 3 === 3 is true
  else if(strokes === par - 1) {
    return names[2]; // exit with "Birdie"
  }
  
  // if strokes equals par.
  // e.g. golfScore(2, 2) a par of 2, and strokes is 2.
  // 2 equals 2, 2 === 2 is true
  else if(strokes === par) {
    return names[3]; // exit with "Par"
  }
  
  // if strokes equals par plus 1.
  // e.g. golfScore(2, 3) a par of 2 plus 1 is 3, and strokes is 3.
  // 3 equals 3, 3 === 3 is true
  else if(strokes === par + 1) {
    return names[4]; // exit with "Double Bogey"
  }
  
  else if(strokes === par + 2) {
    return names[5]; // exit with "Bogey"
  }
  
  // if strokes is larger than or equals par plus 3.
  // e.g. golfScore(2, 7) a par of 2 plus 3 is 5, and strokes is 7.
  // 7 is larger than or equal to 5, 7 >= 5 is true
  else if(strokes >= par + 3){
    return names[6]; // exit with "Go Home!"
  }
  
  // if none of the condition above are met then
  // return with "Change Me"
  else {
    return "Change Me";
  }
}

// calling golfScore passing in a par of 5 and strokes of 4
golfScore(5, 4); // strokes === par - 1, outputs "Birdie"

There is a comment at the end of the function // Only change code above this line. This indicates that the code need changing/refactoring. Without knowing what the question is though, it is not possible to give an answer.

1 Like
5

I understand how to work with an array, but I don’t understand the meaning of these strokes === pairs - 1 or these strokes === pairs or strokes <= pairs - 2

for example, this is what I understand strokes === 1 this means 4 attempts are given if it hits the first time then the name 0 is returned

6

I have commented your code, please read the comments.

7

I don’t understand these comments, I don’t understand

8

Read the code and as you do so, substitute the variables with the values and evaluate the comparisons. You are calling the code as golfScore(5,4) so you will have par=5; strokes=4. Substitute those in the code and you have:

if(4 == 1){
  return names[0]
}
else if(4 <= 5 - 2){
  return names[1]
}
else if(4 == 5-1){
return names[2]
}
else if(4 == 5){
  return names[3]
}
else if(4 == 5 + 1){
  return names[4]
}
else if(4 == 5 + 2){
  return names[5]
}
else if(4 >= 5 + 3){
  return names[6]
}
else{
  return "Change Me";
}

Now evaluate each condition, paying attention to operator precedence.

Is 4 == 1 true? No, so go to the next branch.
Is 4 <= 5 - 2 true? Do the math first, so you have 4 <= 3. It is false, so move to the next branch.
Is 4 == 5 - 1 true? Do the math first, so you have 4 == 4. It is true, so follow this branch.
Return names[2].

1 Like
9

So… uhm… did you read the previous examples and lessons?

FCC is pretty good at not giving you an example without a basis of understanding it…

10

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