How to determine if a Vue plugin is registered?

Question

Vue.js

The scripts will have to work in an unknown environment, where Vue and some other libraries may or may not already be loaded.

To do this, I created the following initialization skeleton:

init: function (conteinerId,tags) {
        tags = tags || [];
        
        this._checkDependencies().then(() => {
            
            
            console.log('Go')
        });
        
    },
    
    _checkDependencies: function () {
        
        var promise = new Promise(function(resolve, reject) {resolve(true);});
        
        if (typeof Vue == 'undefined')
                promise = promise.then(script => this._loadScript('//cdn.jsdelivr.net/npm/[email protected]/dist/vue.js'));
        
        if (typeof axios == 'undefined')
                promise = promise.then(script => this._loadScript("//unpkg.com/axios/dist/axios.min.js"))
        
        promise = promise.then(script => this._loadScript("//unpkg.com/[email protected]/dist/vue-axios.min.js"))
        
        return promise;
    },
    
    _loadScript: function (src) {
        return new Promise(function(resolve, reject) {
            let script = document.createElement('script');
            script.src = src;
            script.type = 'text/javascript';
            
            script.onload = () => resolve(script);
            script.onerror = () => reject(new Error(`Ошибка загрузки скрипта ${src}`));
            
            document.head.append(script);
        });
    }

And everything is fine if vue-axios is not loaded yet on the page, but if it is, the error Uncaught TypeError: Cannot redefine property: axios crashes due to the fact that I reload it. How to check if vue-axios is already loaded? Or that it is at least registered with Vue?

I tried to look at the plugin code, but it's not very clear to me - I don't see that it creates any global variables for the presence of which you can navigate.

Answer 1

Doesn't the plugin add something like Vue.axios?