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

Map Characters of String to New String

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.

For more Practice: Solve these Related Problems:

• Write a JavaScript program that applies a transformation function to each character of a string and returns the new string.
• Write a JavaScript function that maps over a string’s characters, modifies them, and concatenates the results into a new string.
• Write a JavaScript program that converts a string by applying a provided callback to every character and joining the results.

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