Vue.js Computed Properties Quiz

Computed Properties

• Computed properties are defined in the 'computed' section of a Vue instance.
• They function like data properties but are dynamic, automatically updating when a dependency changes.
• Unlike methods, computed properties are called reactively based on their dependencies instead of being invoked directly.

Vue Watchers

• Watchers, defined in the 'watch' section of a Vue instance, monitor changes to a specific data property.
• They trigger automatically upon data property changes, making them suitable for actions that depend on specific data updates.
• Watchers pass both new and old values as arguments when triggered, allowing for detailed state management.

Watchers vs Methods

• Methods are explicitly invoked through events in HTML, often responding to user actions.
• Watchers react to changes in data properties without direct invocation, focusing on side effects resulting from data updates.
• Methods receive the event object as input automatically, while watchers do not require manual calls.

Watchers vs Computed Properties

• Watchers track single properties, while computed properties can depend on multiple data sources.
• Computed properties act like reactive data properties, automatically adjusting and providing live updates based on their dependencies without additional coding.

Vue v-if Directive

• The v-if directive is used for conditional rendering, allowing developers to show or hide elements based on specific conditions.
• It can be combined with v-else-if for more intricate conditional logic (e.g., displaying different messages based on stock levels).

Vue v-show Directive

• The v-show directive toggles visibility by manipulating the CSS 'display' property, offering a simpler approach than v-if.
• Unlike v-if, v-show keeps the element in the DOM, which can improve performance when switching visibility frequently.

Vue v-for Directive

• The v-for directive enables list rendering by iterating over an array and creating elements dynamically.
• Elements generated through v-for update automatically when the underlying array changes, ensuring UI consistency with data state.

Vue v-on Directive

• The v-on directive facilitates event handling in Vue applications, allowing developers to specify responses to events like clicks or key inputs.
• It supports shorthand syntax (@) for cleaner code and can be easily used with v-for to handle events for iterated elements.

Vue Methods

• Methods in Vue are functions declared under the 'methods' property, utilized for event handling and logic.
• They are capable of executing complex operations when triggered by user interactions.

Vue Event Modifiers

• Event modifiers enhance the functionality of events, allowing for refined control over when and how methods are executed.
• Common examples include preventing default actions (prevent), limiting executions (once), and binding methods to specific keyboard keys (keyup.enter).

Vue Forms

• Vue improves form handling with the v-model directive, establishing two-way data binding between input elements and Vue data properties.
• Changes in input fields update the Vue instance and vice versa, creating a responsive user experience.

Dynamic Checkboxes

• Implement v-model for checkboxes to manage binary states (e.g., marking items as important) within forms.
• Enhances the interactivity and user engagement of forms by reflecting changes immediately in the Vue data instance.

Summary of Key Points

• Computed properties change dynamically based on dependencies.
• Watchers provide a reactive mechanism for monitoring data changes and executing related actions.
• v-if and v-show are used for conditional rendering, each with different DOM manipulation strategies.
• Event handling in Vue is robust, enabling complex interactions through methods, event modifiers, and reactive data binding with v-model.