LU05d - v-show [BZZ

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====== LU05d - v-show ======

===== Learning ojectives =====
  - I can explain what directive v-show fulfil within the DOM.
  - I can prove the visibility of objects using v-show.
  - I can use the v-show directive.

====== Sources ======
  * [[https://www.w3schools.com/vue/vue_v-show.php|W3School | W3School | Conditional Rendering - v-show]]
  * [[https://vuejs.org/guide/essentials/conditional.html#v-show | Vuejs.org | Conditional Rendering - v-show]]
 
===== Introduction ====
The v-show directive in Vue.js is used to conditionally display elements based on a boolean expression. //Unlike v-if, which completely removes elements from the DOM when the condition is false//, v-show toggles the CSS display property, keeping the element in the DOM but hiding it visually. This makes v-show more efficient when elements need to be frequently shown or hidden without re-rendering. It is best suited for UI toggles, such as modals, dropdowns, or tooltips. 

The syntax is simple: isVisible controls the visibility of the element dynamically

  <div v-show="isVisible">Content</div>

===== Example =====
  <template>
    <div>
      <button @click="isVisible = !isVisible">
        Toggle Message
      </button>
      <p v-show="isVisible">Hello, Vue.js!</p>
    </div>
  </template>

  <script>
    export default {
      data() {
        return {
          isVisible: true
        };
      }
    };
  </script>

**Explanation:**
  * The v-show="isVisible" directive controls the visibility of the <p> element.
  * Clicking the button toggles isVisible between true and false.
  * Instead of removing the element from the DOM, Vue modifies its display property.

===== v-if VS v-show =====
Both, v-if and v-show are conditional rendering, but unlike v-if, the v-show directive **only** make the object of concern **invisible**, for it is yet hidden part of the HTML-DOM. 

===== Demonstration =====

[[https://www.w3schools.com/vue/tryit.php?filename=tryvue_v-show_div2 | v-show VS v-if]]

  * **v-show:** Hides only an object, it is still accessible for fold-in or fold-out
  * **v-if:** The object of concern is no longer existing, as it was destroyed from the HTML-DOM.


^Feature	^v-if	^v-show ^
| DOM Behavior | Completely adds/removes elements from the DOM | Only toggles the display property (keeps elements in the DOM) |
| Performance | Better for infrequent changes (expensive re-rendering) | Better for frequent toggling (faster updates) |
| Usage Case | When elements are rarely shown/hidden | When elements need to be toggled frequently | 
 

===== Vocabulary =====
^ English ^ German ^ 
| conditionally | bedingt |
| to fold in/out | einklppen/ausklappen |

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[[https://creativecommons.org/licenses/by-nc-sa/4.0/|{{https://i.creativecommons.org/l/by-nc-sa/4.0/88x31.png}}]] Volkan Demir