Question

How to replace a character at a specific index in a string with JavaScript

Answer 1

String.prototype.replaceAt = function(i, replacement) {
    return this.substr(0, i) + replacement + this.substr(i + replacement.length);
}
 
let s = "javascript php c++";
 
s = s.replaceAt(2, "W"); 
console.log(s);
 
 
s = s.replaceAt(13, "X"); 
console.log(s);
 
 
s = s.replaceAt(16,  ' '); 
console.log(s); 



 
 
/*
run:
 
jaWascript php c++
jaWascript phX c++
jaWascript phX c +

*/

 

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Answer 2

String.prototype.replaceAt = function(i, replacement) {
  let arr = this.split("");
  arr[i] = replacement;
  return arr.join("");
}
  
let s = "javascript php c++";
  
s = s.replaceAt(2, "W"); 
console.log(s);
  
  
s = s.replaceAt(13, "X"); 
console.log(s);
  
  
s = s.replaceAt(16,  ' '); 
console.log(s); 
 
 
 
  
  
/*
run:
  
jaWascript php c++
jaWascript phX c++
jaWascript phX c +
 
*/

 

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