When developing Vue applications, common anti-patterns include: 1. When dealing with complex logic in the template, the logic should be moved to methods or computed; 2. When abuse of v-if and v-show, the reason should be selected according to the switching frequency; 3. When directly indexing to modify the array or adding object properties to destroy the responsiveness, the mutation method or $set should be used; 4. When excessive nesting causes cumbersome communication of components, state management or provide/inject should be used; 5. When using life cycle hooks incorrectly, attention should be paid to responsibilities at each stage and side effects of cleaning up.

When developing Vue applications, although the framework itself is designed with a relatively friendly and flexible design, it is still easy to get stuck if you do not pay attention to some common problems or misuse methods. Here are some common anti-patterns and practices to avoid that can help you write clearer and maintainable code.

1. Do too much logic in the template

Vue's template syntax is very powerful, but it is also easy for people to "be lazy" to write a lot of logical judgments, calculations and even method calls in the template. This reduces readability and performance.

suggestion:

• Put complex logic into methods or computed
• Template only needs to display data, not process data
• Avoid calling functions in v-for , such as {{ formatData(item) }} , so that each rendering will be executed, affecting performance

For example:

 <!-- Counterexample-->
<div v-for="item in list">
  {{ item.name.split(&#39; &#39;)[0].toUpperCase() }}
</div>

<!-- Correct way-->
<div v-for="item in formattedList">
  {{ item.firstName }}
</div>

Then process the formatting logic in computed .

2. Unreasonable abuse of v-if and v-show

v-if is lazy, and the DOM is not rendered when the condition is false; v-show is displayed hidden through CSS control. Many people will randomly use these two instructions, resulting in unnecessary performance losses or structural confusion.

Recommended usage:

• If the switching frequency is low (such as the page changes very little after loading), use v-if
• If you switch frequently, use v-show first
• Don't abuse v-if on components, especially components with internal state, as repeated destruction and reconstruction will cause state loss

3. Data changes are not responsive

Vue's responsive system relies on the data tracking mechanism. If you directly modify array elements through indexes or add new attributes to objects, these operations will not trigger updates.

Solution:

• When modifying the array, use the mutation methods provided by Vue (such as push , splice , etc.)
• Use this.$set() or Vue.set() when adding object properties

example:

 // Error method this.items[index] = newValue;

// The correct way is this.$set(this.items, index, newValue);

4. Over-necked component communication

Passing values ??between parent-child components is the basic ability of Vue, but if the hierarchy is too deep and insists on manually passing props and emit events layer by layer, it will become difficult to maintain.

Optimization direction:

• Manage global state using Vuex or Pinia
• For small and medium-sized projects, you can also consider using provide/inject to pass data across levels
• Combine component logic appropriately to avoid over-split

5. Ignore the correct use of life cycle hooks

Vue's lifecycle hook provides many control points, but some people will do things they shouldn't do in the wrong stage, such as accessing the DOM in created , or initiating an asynchronous request in mounted without processing the load state.

suggestion:

• created : suitable for initializing data and setting default values
• mounted : can safely access the DOM, suitable for binding third-party libraries or initiating first requests
• Be careful to clean up side effects, such as removing event listeners in beforeUnmount or canceling unfinished requests

Basically these common pitfalls. Avoiding them is not complicated, but it is indeed easy to ignore in actual development, especially when catching up with progress. Keep these points in mind, the written Vue code will be more stable and easier to maintain.

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