Replacing dots with dashes in a string using JavaScript

We are required to write a JavaScript function that takes in a string and replaces all appearances of dots(.) in it with dashes(-).

Input

const str = 'this.is.an.example.string';

Expected Output

const output = 'this-is-an-example-string';

All appearances of dots(.) in string str are replaced with dash(-)

Method 1: Using replace() with Regular Expression

The most efficient approach is using the built-in replace() method with a global regular expression:

const str = 'this.is.an.example.string';

const replaceDots = (str = '') => {
    return str.replace(/\./g, '-');
};

console.log(replaceDots(str));

this-is-an-example-string

Method 2: Using split() and join()

Another clean approach is splitting the string by dots and joining with dashes:

const str = 'this.is.an.example.string';

const replaceDots = (str = '') => {
    return str.split('.').join('-');
};

console.log(replaceDots(str));

this-is-an-example-string

Method 3: Using Manual Loop

For educational purposes, here's a manual iteration approach:

const str = 'this.is.an.example.string';

const replaceDots = (str = '') => {
    let res = "";
    const { length: len } = str;
    for (let i = 0; i < len; i++) {
        const el = str[i];
        if (el === '.') {
            res += '-';
        } else {
            res += el;
        }
    }
    return res;
};

console.log(replaceDots(str));

this-is-an-example-string

Performance Comparison

Handling Edge Cases

const replaceDots = (str = '') => {
    return str.replace(/\./g, '-');
};

// Test edge cases
console.log(replaceDots(''));           // Empty string
console.log(replaceDots('no-dots'));   // No dots
console.log(replaceDots('...'));       // Only dots
console.log(replaceDots('.start.end.')); // Dots at boundaries

no-dots
---
-start-end-

Conclusion

Use str.replace(/\./g, '-') for the best performance and readability. The split().join() method is also clean and intuitive for simple character replacements.