What are some effective methods for troubleshooting Vue.js computed properties and templates?

I am facing challenges with debugging in Vue.js, especially when it comes to debugging computed properties or data values in templates.

Currently, I am using the IIFE method for debugging as shown in :

<h2 dir="auto">
  {{(function(){debugger;let temp = headerMessage})()  ||  headerMessage}}
</h2>

Another issue I encountered is related to source maps in Chrome for debugging Vue files. The duplicates with different codes from one file can be confusing and not helpful for effective debugging (the example of panel.vue shown below is not the actual one from my project). I want to see the original panel.vue file to debug effectively:

I am looking for a solution to fix this problem and wondering if there is a way to set breakpoints properly and debug these specific parts in Vue.js?

typescriptvue.jstemplatesdebuggingcomputed-properties

Answer №1

If you're looking to enhance your Vue.js development experience, I recommend trying out the vue-dev-tools browser extension. This handy tool allows you to inspect each component's data, computed properties, and more.

You can easily download and install it from any popular browser extension store, such as Chrome Web Store, Mozilla Add-ons, etc.

For more information and updates, you can also check out the official Vue Dev Tools repository.

Answer №2

When troubleshooting template issues, it is recommended to simplify complex logic by moving it into a method for easier debugging using standard tools.

Vue computed issues usually fall into one of three categories:

1. Debugging complex logic within the computed property

To tackle this, consider extracting the complexity into a separate method and calling it from the computed property. This allows for effective debugging with tools like debugger, console.log, or breakpoints.

It's crucial to ensure that any reactive data/props remain within the computed definition to maintain reactivity. The computed should mainly focus on gathering arguments for the method carrying out the actual processing.

2. Simple logic in the computed not functioning as expected

In such cases, utilize Vue devtools to inspect the component associated with the computed property. Use $vm to analyze the component's state and test snippets of the computed logic until the problem is identified.

You can directly access data/props/computeds using $vm, e.g., $vm.myProp.

Remember to select a component in devtools for $vm to work properly.

3. Computed property relies on reactivity but remains unchanged

A similar approach as #2 is suggested here.

Check for typos in the names of reactive elements being used. If an evaluation consistently results in false, there might be a typo pointing to a nonexistent property, returning undefined (falsy).

Additionally, when depending on changes in nested state for data or props, ensure the appropriate use of Vue.set / this.$set.

Answer №3

Another point to keep in mind, as mentioned by @Toodoo, is that for a Computed property to be displayed in the section containing data and variables, it must be included in the list of exported properties within the "return" statement at the end of your setup.

return {Component1, data, ComputedProp }

By doing this, the Computed property will then appear in the appropriate section.

In simpler terms, whatever you make visible or accessible to the App, you also do so for the developer tools (which is a crucial detail).

Answer №4

In my experience, I found that adding the following code inside your computed property was incredibly beneficial:

try { ... } catch(e) { console.log(e); }
.

Consider relocating your return statement to encapsulate the issue and contain the questionable code within the try block.

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