Using The .replaceAll() on a string literal array in Javascript

Question

Goal: Use an array method to remove the strings get, right, the, first, time and replace them with the single string know in secretMessage array.

Plan Define a function to text in the rain, the old string, and the new string and use to .replaceall() methods and pass each one of the different arguments through one at a time, reassigning the array each call.

Code Thus Far

let secretMessage = ['Learning', 'is', 'not', 'about', 'what', 'you', 'get', 'easily', 'the', 'first', 'time,', 'it', 'is', 'about', 'what', 'you', 'can', 'figure', 'out.', '-2015,', 'Chris', 'Pine,', 'Learn', 'JavaScript'];
    

function replaceWords(orginalArray,oldString,updatedString){=
  let updatedArray= orginalArray.replaceAll(oldString,updatedString);//Not Sure If I need to wrap this in []
  return updatedArray;
}
secretMessage = replaceWords(secretMessage,'get','know');
secretMessage = replaceWords(secretMessage,'right','know');
secretMessage = replaceWords(secretMessage,'the','know');
secretMessage = replaceWords(secretMessage,'first','know');
secretMessage = replaceWords(secretMessage,'time','know');

console.log(secretMessage);

Current Results

let updatedArray= orginalArray.replaceAll(oldString,updatedString);
                               ^

TypeError:

orginalArray.replaceAll is not a function at replaceWords

I generally would just loop through the main array containing safe-words. Then check if the other array includes the selected safe-word (as it's looping). Then I would splice(index,1) and go from there. Reason for backwards is to not mess up index when we break it down on removals. — BGPHiJACK, Dec 31 '21 at 13:34
`.replaceAll()` is a **string** method, not an array method. — Pointy, Dec 31 '21 at 13:34
Apart from what @Pointy already mentioned, please also pay attention to the difference between the strings `'time,'` and `'time'` — secan, Dec 31 '21 at 13:48

score 1 · Answer 1 · answered Dec 31 '21 at 13:43

As stated by @Pointy's comment, replaceAll() is a string method, it's not available on an array.

So we'll need a way to apply something on each array index.

Luckily map() does exactly that:

The map() method creates a new array populated with the results of calling a provided function on every element in the calling array.

let secretMessage = ['Learning', 'is', 'not', 'about', 'what', 'you', 'get', 'easily', 'the', 'first', 'time,', 'it', 'is', 'about', 'what', 'you', 'can', 'figure', 'out.', '-2015,', 'Chris', 'Pine,', 'Learn', 'JavaScript'];
    

function replaceWords(orginalArray,oldString,updatedString){
  return orginalArray.map(item => {
    return item.replaceAll(oldString, updatedString)
  });
}
secretMessage = replaceWords(secretMessage,'get','know');
secretMessage = replaceWords(secretMessage,'right','know');
secretMessage = replaceWords(secretMessage,'the','know');
secretMessage = replaceWords(secretMessage,'first','know');
secretMessage = replaceWords(secretMessage,'time','know');

console.log(secretMessage);

Apollo79 · Answer 2 · 2021-12-31T20:51:01.647

replaceAll is String function, not an Array function. If you want to replace a word that maybe exists as value in an array, you have to walk through that array. Your code would look like this:

let secretMessage = ['Learning', 'is', 'not', 'about', 'what', 'you', 'get', 'easily', 'the', 'first', 'time,', 'it', 'is', 'about', 'what', 'you', 'can', 'figure', 'out.', '-2015,', 'Chris', 'Pine,', 'Learn', 'JavaScript'];
    

function replaceWords(orginalArray,oldString,updatedString){
  /* because your array values are just single words 
  and you want to replace the whole word with another whole word, 
  you can use string comparison instead of replaceAll() */
  
  let updatedArray= orginalArray.map(string => (string == oldString ? updatedString : string));
  return updatedArray;
}
secretMessage = replaceWords(secretMessage,'get','know');
secretMessage = replaceWords(secretMessage,'right','know');
secretMessage = replaceWords(secretMessage,'the','know');
secretMessage = replaceWords(secretMessage,'first','know');
secretMessage = replaceWords(secretMessage,'time','know');

console.log(secretMessage);

score 1 · Accepted Answer · answered Dec 31 '21 at 14:04

Just for "fun", a solution using both an array method (Array.prototype.join()) and replaceAll() (String.prototype.replaceAll()) and close to your original idea, could be:

function replaceWords(arr, oldStr, newStr) {
  return arr.join(' ')          // join all the array items into a single space-separated string
    .replaceAll(oldStr, newStr) // call `replaceAll()` on the newly created string
    .split(' ');                // split the string back into an array
}

let secretMessage = ['Learning', 'is', 'not', 'about', 'what', 'you', 'get', 'easily', 'the', 'first', 'time,', 'it', 'is', 'about', 'what', 'you', 'can', 'figure', 'out.', '-2015,', 'Chris', 'Pine,', 'Learn', 'JavaScript'];

secretMessage = replaceWords(secretMessage, 'get', 'know');
secretMessage = replaceWords(secretMessage, 'right', 'know');
secretMessage = replaceWords(secretMessage, 'the', 'know');
secretMessage = replaceWords(secretMessage, 'first', 'know');
secretMessage = replaceWords(secretMessage, 'time', 'know');

console.log(secretMessage);

Having said that, I think nobody would do it in that way in real life ;)

Thanks! Opens my Mind up -if the map method didn't exist I def would have been asking how to go this route — Terry Brooks Jr, Dec 31 '21 at 14:21

Shiva · Answer 4 · 2021-12-31T14:21:21.513

-1

You can extend the array functionality to match your requirement. But not recommended.

Just add below code before your array declaration and your code should work.

Array.prototype.replaceAll = function(oldString, updatedString){
    return this.slice().map((str)=>((str === oldString)?updatedString:str));
}

edited Dec 31 '21 at 14:21

answered Dec 31 '21 at 14:10

Shiva

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wardialer · Answer 5 · 2021-12-31T13:46:01.320

replaceAll() works for strings not arrays. Try the example below.

let secretMessage = ['Learning', 'is', 'not', 'about', 'what', 'you', 'get', 'easily', 'the', 'first', 'time,', 'it', 'is', 'about', 'what', 'you', 'can', 'figure', 'out.', '-2015,', 'Chris', 'Pine,', 'Learn', 'JavaScript'];
    

function replaceWords(orginalArray,oldString,updatedString){=
  let updatedArray= orginalArray.join().replaceAll(oldString,updatedString).split();
  return updatedArray;
}
secretMessage = replaceWords(secretMessage,'get','know');
secretMessage = replaceWords(secretMessage,'right','know');
secretMessage = replaceWords(secretMessage,'the','know');
secretMessage = replaceWords(secretMessage,'first','know');
secretMessage = replaceWords(secretMessage,'time','know');

console.log(secretMessage);

`.split()` is also a string method, not an array method. – Pointy Dec 31 '21 at 13:43 — Pointy, Dec 31 '21 at 13:43

Using The .replaceAll() on a string literal array in Javascript

5 Answers5