JavaScript: Create a new string with the results of calling a provided function on every character in the calling string

JavaScript fundamental (ES6 Syntax): Exercise-83 with Solution

Write a JavaScript program to create an updated string with the results of calling a provided function on every character in the called string.

• Use String.prototype.split('') and Array.prototype.map() to call the provided function, fn, for each character in str.
• Use Array.prototype.join('') to recombine the array of characters into a string.
• The callback function, fn, takes three arguments (the current character, the index of the current character and the string mapString was called upon).

Sample Solution:

JavaScript Code:

//#Source https://bit.ly/2neWfJ2
// Define the function 'mapString' to map each character of a string to a new character using a given function.
const mapString = (str, fn) =>
  // Split the string into an array of characters, apply the function to each character along with its index, and join the resulting characters back into a string.
  str.split('').map((c, i) => fn(c, i, str)).join('');

// Example usage:
console.log(mapString('Javascript exercises', c => c.toUpperCase())); // Outputs: "JAVASCRIPT EXERCISES"

Output:

JAVASCRIPT EXERCISES

Visual Presentation:

Flowchart:

Live Demo:

See the Pen javascript-basic-exercise-83-1 by w3resource (@w3resource) on CodePen.

Improve this sample solution and post your code through Disqus

Previous: Write a JavaScript program to map the values of an array to an object using a function, where the key-value pairs consist of the original value as the key and the mapped value.
Next: Write a JavaScript program to create an object with the same keys as the provided object and values generated by running the provided function for each value.