10. Using filter local to component

We can create a component filter by putting our filter in filters in the component script.

Here the filter checks if all characters are capital. Should the string be empty, we will get a return value of false, as we never enter the for loop.

Each time we get a capital character, the retV variable is set as true.

For a character not a capital letter, we immediately return a false.

Thus should we complete the entire for loop it means all characters are capital.

This is the App.vue file:

<template>
  <div>
    <label>Enter string:</label>
    <input type="text" v-model="val">
    <h2>Is string all capital?</h2>
    <h2>{{val|isAllCap}}</h2>
  </div>
</template>

<script>
export default {
  data() {
    return {
      val: ""
    }
  },
  filters: {
    isAllCap: function(v) {
      let retV = false;
      for (let i = 0; i < v.length; i++) {
        let c = v.charAt(i);
        if (c >= 'A' && c <= 'Z') retV = true;
        else return false;
      }
      return retV;
    }
  }
}
</script>

<style>
h2 {
  color: blue;
  background-color: orange;
  width: 400px;
  margin: 50px auto;
  text-align: center;
}
</style>

This is the output: