Employing global variables in JavaScript files with Vue3

Question

Employing global variables in JavaScript files with Vue3

In my Vue3 project, I have defined global variables like this:

 app.config.globalproperties.$locale = locale

A composable function has been created to dynamically retrieve these global variables:

import { getCurrentInstance ) from 'vue'
export function useGlobals(type) {
  const app = getCurrentInstance()
  const global = app.appContext.config.globalProperties[`$${type}`]
  return { global }
}

These composable functions are then imported and used in Vue components:

import { useGlobals } from '../path'
const { global } = useGlobals('locale')

This allows the global variables to be accessed. However, an issue arises when trying to import the composable function in JavaScript files, as the appContext is undefined there.

My question is, is there a way to access global variables or the appContext in JavaScript files?

javascript vue.js global-variables vuejs3 vue-composition-api

Answer 1

Answer №1

After receiving a valuable suggestion from @tao (by the way, it's not possible to retrieve appContext from the app itself, but that sparked an idea :)), the issue has been resolved.

I have added another export in main.js, following the creation of the app, containing all global properties:

const globals = app.config.globalProperties
export { globals }

Alternatively, as suggested by @tao, it can be exported as a function:

export const useGlobals = () => app.config.globalProperties

Now, we are able to import globals into any js file and utilize them like this:

import { globals } from '../path/to/main.js'
globals.$locale

Alternatively, using a function:

import { useGlobals } from '../path/to/main.js'
const { $locale } = useGlobals()

Answer 2

After receiving a valuable suggestion from @tao (by the way, it's not possible to retrieve appContext from the app itself, but that sparked an idea :)), the issue has been resolved.

I have added another export in main.js, following the creation of the app, containing all global properties:

const globals = app.config.globalProperties
export { globals }

Alternatively, as suggested by @tao, it can be exported as a function:

export const useGlobals = () => app.config.globalProperties

Now, we are able to import globals into any js file and utilize them like this:

import { globals } from '../path/to/main.js'
globals.$locale

Alternatively, using a function:

import { useGlobals } from '../path/to/main.js'
const { $locale } = useGlobals()

Answer 3

Answer №2

After trying the solution recommended by @nikola-pavicevic, I encountered a problem with infinite recursion. Each time globals was imported, it triggered a complete run-through of main.js, resulting in the app being initialized and mounted again. While the app seemed to function correctly in production, the Jest unit tests revealed numerous issues caused by this recursive behavior.

To address this issue, I devised a workaround by creating a separate file named GlobalVariableHolder.js with the following content:

const GlobalVariables = {};
export default GlobalVariables;

Subsequently, within main.js, I could import it using:

import GlobalVariables from "./GlobalVariableHolder";

Next, I assigned the variables as follows:

// Be sure to assign the variables to app.config.globalProperties before running this line.
GlobalVariables.variables = app.config.globalProperties;

Once done, when needing these variables in another JS file, the import statement remains unchanged:

import GlobalVariables from "./GlobalVariableHolder";

This approach allows access to all items from

app.config.globalProperties</code like so:</p>
<pre class="lang-js"><code>GlobalVariables.variables.$thisIsAMethod(parameter);

By employing this method, importing GlobalVariableHolder no longer results in setting up a new Vue instance every time.

Answer 4

After trying the solution recommended by @nikola-pavicevic, I encountered a problem with infinite recursion. Each time globals was imported, it triggered a complete run-through of main.js, resulting in the app being initialized and mounted again. While the app seemed to function correctly in production, the Jest unit tests revealed numerous issues caused by this recursive behavior.

To address this issue, I devised a workaround by creating a separate file named GlobalVariableHolder.js with the following content:

const GlobalVariables = {};
export default GlobalVariables;

Subsequently, within main.js, I could import it using:

import GlobalVariables from "./GlobalVariableHolder";

Next, I assigned the variables as follows:

// Be sure to assign the variables to app.config.globalProperties before running this line.
GlobalVariables.variables = app.config.globalProperties;

Once done, when needing these variables in another JS file, the import statement remains unchanged:

import GlobalVariables from "./GlobalVariableHolder";

This approach allows access to all items from

app.config.globalProperties</code like so:</p>
<pre class="lang-js"><code>GlobalVariables.variables.$thisIsAMethod(parameter);

By employing this method, importing GlobalVariableHolder no longer results in setting up a new Vue instance every time.

Answer 5

Answer №3

Stop trying to manually build your composable functions to access global properties, just utilize the provide/inject feature instead.

To learn more about this method, refer to the official documentation at: https://vuejs.org/api/composition-api-dependency-injection.html#provide

Answer 6

Stop trying to manually build your composable functions to access global properties, just utilize the provide/inject feature instead.

To learn more about this method, refer to the official documentation at: https://vuejs.org/api/composition-api-dependency-injection.html#provide

Employing global variables in JavaScript files with Vue3

Answer №1

Answer №2

Answer №3

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