Mapping string to Numerals in JavaScript

We are required to write a JavaScript function that takes in a string. It should print out each number for every corresponding letter in the string.

Letter to Number Mapping

Each letter corresponds to its position in the alphabet:

a = 1
b = 2
c = 3
d = 4
e = 5
...
y = 25
z = 26

Note: The function should remove any special characters and spaces, processing only alphabetic characters.

Example Input and Output

If the input is:

"hello man"

Then the output should be:

"8,5,12,12,15,13,1,14"

Implementation

const str = 'hello man';

const charPosition = str => {
    str = str.split('');
    const arr = [];
    const alpha = /^[A-Za-z]+$/;
    
    for(let i = 0; i 

8,5,12,12,15,13,1,14


How It Works

The function works by:

• Converting the string into an array of characters using split('')
• Using a regex pattern /^[A-Za-z]+$/ to identify alphabetic characters
• Converting each letter to lowercase and using charCodeAt(0) - 96 to get its position (since 'a' has ASCII value 97)
• Collecting all positions in an array and converting to a comma-separated string

Alternative Approach

Here's a more concise version using modern JavaScript methods:

const mapStringToNumbers = (str) => {
    return str.toLowerCase()
        .split('')
        .filter(char => char >= 'a' && char  char.charCodeAt(0) - 96)
        .join(',');
}

console.log(mapStringToNumbers('hello man'));
console.log(mapStringToNumbers('JavaScript123!'));

8,5,12,12,15,13,1,14
10,1,22,1,19,3,18,9,16,20

Conclusion

This function effectively maps each letter to its alphabetical position while ignoring non-alphabetic characters. The charCodeAt() method combined with ASCII arithmetic provides an efficient solution for character-to-number conversion.