Wow, those were the days! It just came to my mind now, a few years ago I was working on a project with Vue.js. The frontend was working flawlessly, everything was going great. Then I noticed that my beloved Vue components started behaving as if they didn’t exist anymore when changing pages. I was pretty much panicking at that moment. I wondered, what can I do about this? Is there a way for Vue to remember its components in memory? I thought, there must be an easy solution.
That’s when I encountered Dynamic Components and keep-alive. While initially it sounded a bit complicated, the core idea was quite simple. Think of it like this: you’ve built a house and filled it with beautiful objects. These objects are your components. Instead of rebuilding everything from scratch every time you enter the house, wouldn’t it be practical to leave some objects as they are and only use what you need? That’s precisely what keep-alive does. It keeps your components in memory, and when the page refreshes or you switch to another component, it doesn’t recreate them but keeps them waiting as if they never left.
By the way, when we travel around Bursa with family, you know, I like city tours. During one such trip, we visited a museum with incredible artifacts. Our guide explained how some artifacts have been preserved over time, looking just as if they were made yesterday. Keep-alive is like those artifacts, preserving our components from the effects of time and keeping their original state. 🙂 Pretty cool, right?
Now, let’s talk about dynamic components. These allow us to load specific components dynamically. For example, when you click a button and an element needs to appear on the screen, dynamic components come into play. They load only when needed and disappear once their job is done. This makes our application load faster because instead of loading everything upfront, it loads only what is necessary. Also, I used a similar approach in my own C# REST API backend. Based on incoming requests from the frontend, I dynamically determine which service to run. This created a more flexible and performant structure.
So, how do we combine these two? Vue provides a special `
Typically, when a component is removed from the DOM, it gets destroyed. But with `
It’s like taking a snapshot of your components and saving it. When you come back, you show that snapshot instead of drawing from scratch.
Let’s look into the code now. Suppose we send data from Vue to a C# REST API, using dynamic components and keep-alive. First, we need to load a component dynamically on the Vue side. Then, from this component, we will send data to our backend using an HTTP request. It’s similar to the logic I use when developing web services: receiving data from frontend and processing it.
For example, imagine a form filled out by users, and this information is saved to a C# backend. Using Vue’s dynamic component and keep-alive, you can ensure that after the user fills out the form and navigates elsewhere, your data persists. You can then trigger a request from within the component to send this data to the API via a button click or other event.
Whenever I encounter such situations in my programs, I try to test with sample code first. Recently, I found a bug and couldn’t solve it initially. Then I decided to find some example code and implement it. It worked! 🙂 That’s how dynamic components and keep-alive work. First, you understand the concept, then write and test your code.
Now, let’s look at some code. Suppose we have a form and we want to send its data. Initially, I might make a mistake and not store or load the data properly. But after learning the correct way, things get much easier. It’s like making mistakes first, then learning the right approach. Life is like that, and coding is too.
Here’s an example code snippet:
// WRONG WAY (Just sending data, component state lost)
<template> <div> <input v-model="userData.name" placeholder="Your Name"> <button @click="submitForm">Send</button> </div> </template> <script> export default { data() { return { userData: { name: '' } }; }, methods: { async submitForm() { // API call would happen here but the component is gone, data lost console.log('Data Sent:', this.userData.name); // await fetch('/api/users', { method: 'POST', body: JSON.stringify(this.userData) }); } } } </script>This example shows that if the component is removed from the DOM, `userData.name`’s data will be lost. Navigating away and returning results in an empty input. Not very practical, right?
Now, let’s improve it using keep-alive and dynamic components, focusing on maintaining the data and being able to send it later:
// CORRECT WAY (keeping component in memory with keep-alive and sending data)
<template> <div> <keep-alive> <component :is="currentComponent" :user-data="userData"></component> </keep-alive> <button @click="currentComponent = 'UserProfileForm'">Profile Form</button> <button @click="sendDataToApi">Send All Data</button> </div> </template><script> import UserProfileForm from './UserProfileForm.vue'; // Dynamically loaded component
export default { components: { UserProfileForm }, data() { return { currentComponent: null, userData: { name: '', email: '' } // Store multiple data items }; }, methods: { async sendDataToApi() { console.log('Data sent to API:', this.userData); // Actual API request goes here // await fetch('/api/users', { method: 'POST', body: JSON.stringify(this.userData) }); } } } </script>
In this setup, `
In summary, dynamic components and keep-alive are powerful tools in Vue.js applications. They help improve performance and user experience. Using the duo in complex UI or multi-step workflows makes development much easier. Understand the concept and the rest will come naturally. With these tools, you can create more seamless and user-friendly web applications. Isn’t that great?