How to insert space in CamelCase string?

I've done an example to implement in your code:

  

var regx1 = texto.match (/ [A-Z] / gm) [1]: In this line I get the second occurrence of uppercase letter V .

  

text = text.replace (regx1, '' + regx1): In this line I change V by space and re-enter it with all text after it.

new Vue({
  el: '#app',
  data: {
    stringOriginal: 'PageViews'     
  },
  methods: {
    stringSeparada() {
     var texto = this.stringOriginal;
     var regx1 = texto.match(/[A-Z]/gm)[1];
     texto = texto.replace(regx1,' '+regx1);
     return texto  
    }
  }
})

<script src="https://cdn.jsdelivr.net/npm/vue"></script><divid="app">

  <input type="text" v-model="stringOriginal" /> <br/>
  
  <p>
    Separada: {{ stringSeparada() }}
  </p>

</div>

I believe the simplest way would be to just use the String.replace() with a regex that will match only uppercase.

If you read this session of the documentation of String.replace() , you will see that the second parameter can be a function or a string. If you use a string you can use some special characters to gain some more functionality. These characters are:

• $& : Replaces with the married string. Ex.:

  "...abc123def...".replace(/\d+/, '{{$&}}') 
  // output: "...abc{{123}}def..."
  

• $' : Replaces the previous part with the married string

  "...abc123def...".replace(/\d+/, '{{$'}}')
  // output: "...abc{{...abc}}def..."
  

• $' : Replace with the back part of the married string

  "...abc123def...".replace(/\d+/, "{{$'}}")
  // output: "...abc{{def...}}def..."
  

• $n : Replace with the nth married group in Regex

  "00011122233".replace(/(\d{3})(\d{3})(\d{3})(\d{2})/, "$1.$2.$3-$4")
  // output: "000.111.222-33"
  

So you just have to do a simple replace with the regex and it would be solved:

"PageView".replace(/[A-Z]/g, " $&").trim()

* I used the trim to remove the space if the first letter is uppercase. It's simpler than creating a more complex Regex.

In the final version of the code I added "support" to the accent. Actually the "support" is for a very specific range based on the answers this question .

Below the final code, simple and functional:

var regex = /([A-ZÀ-Þ])/gu;

new Vue({
  el: '#app',
  data: { original: 'PageViewÁcentoTeste'},
  computed: {
    modificada: function() {
      return this.original.replace(regex, ' $1').trim();
    }
  }
});

<script src="https://cdn.jsdelivr.net/npm/vue"></script><divid="app">
  <input v-model="original">
  <span>"{{ modificada }}"</span>
</div>