countConsonants()

Step 1: Understand the problem

The task is to write a Javascript function countConsonants that receives a string word as parameter, and returns the number of consonants in the string.

Before we start coding, let's understand what a consonant is. In English, a consonant is any letter in the alphabet, in the lower or upper case, except for the vowels "A, E, I, O, U".

We are going to approach this problem in a very straightforward way: we will iterate over the string, check if each character is a consonant and, if it is, increment a counter.

function countConsonants(word) {
  // We will fill this code block in the next steps
}

Step 2: Initializing the counter

We need a variable to keep track of how many consonants we have found so far. Let's name this variable count and set it initially to 0.

function countConsonants(word) {
  let count = 0;
}

Step 3: Iterating over the string

We will use a for..of loop to iterate over each character in the string. For now, we will just print the character.

function countConsonants(word) {
  let count = 0;
  
  for (let char of word) {
    console.log(char);
  }
}

Step 4: Checking if character is a consonant

To check if a character is a consonant, we will use a trick: we check if it not a vowel. For this, we create a string with all vowels (in both cases) and check if the character is not in this string.

If the character is not a vowel, it is a consonant, then we increment the count variable.

function countConsonants(word) {
  let count = 0;
  const vowels = 'aeiouAEIOU';
  
  for (let char of word) {
    if (!vowels.includes(char)) {
      count++;
    }
  }
}

Step 5: Returning the count

In the previous step, we incremented the count variable each time we found a consonant in the word. The last step is to return this count as the result of the function.

function countConsonants(word) {
  let count = 0;
  const vowels = 'aeiouAEIOU';
  
  for (let char of word) {
    if (!vowels.includes(char)) {
      count++;
    }
  }
  
  return count;
}

Conclusion

We have successfully created a JavaScript function that counts the number of consonants in a given word. It starts by initializing a counter to zero, then it starts reading the word character by character. If a character is not a vowel, it is a consonant and is considered in the total count. In the end, after reading all the characters in the word, the function returns the count of consonants.