Switching between Vue 2 and Vue 3 to run tests with Composition API

[dobromir-hristov]

Summary

I tried using vue-demi-switch 2 vue2 and defining "vue2": "npm:vue@2" in my package.json, but when I run tests, the @vue/composition-api breaks, because it imports Vue as var Vue = require('vue');

Do you have any advice on how to proceed with this? I saw vueuse/core uses this approach but I couldnt see if you have a fix for this.

You can see this in https://github.com/vuelidate/vuelidate/tree/next

[antfu]

@dobromir-hristov Sorry for the delay, what's the error message the plugin throws? You can run install() from vue-demi at the very beginning of your entry (setup file). It should feed the plugin with the right package.

[dobromir-hristov]

Its OK I got it working, in be it a hackier way :D https://github.com/vuelidate/vuelidate/blob/next/scripts/swap-vue.js

As I said the composition API imports vue from vue and aliasing as vue2 did not do the job for some reason :/

[antfu]

Glad to know you get it to work. The plugin should only import Vue before installing, it should work for custom Vue instance (where vue demi feed it to) after the installations. 🤔

[renatodeleao]

Just had the same issue as @dobromir-hristov, but on my end was related to @vue/test-utils.

I'm trying make a simple library isomorphic, and the default version is vue 2. I've aliased "vue3": "npm:vue@3" as documented on readme. On testing, I had to do the same for "@vue/test-utils-vue3": "@npm:@vue/test-utils@^2.0.0" and added some test-utils middleware using vue-demi to require the appropriate testing package for the vue version.

The problem was also that @vue/test-utils requires var Vue = require('vue'); under the hood, which refers to vue 2 (the default). The swap-vue.js script from @dobromir-hristov saved the day, so this is a more of thank you both post, because I don't know how could vue-demi fix this issue.