I don’t think you should worry so much about it since you’re not using any other framework together. For example if you use vuejs with symfony it will put inside the directory . /assests/vuejs or . /Assets/somethings, in the case of the Variable will be inside . /Resources/Assets/js. For example:
.
├── laravel
│   ├── app
│   ├── public
│   └── resources
│       └── assets
│           └── vuejs
└── symfony
    ├── assets
    │   └── vuejs
    ├── public
    └── src
So if you want to follow the +- the same concept of the guys will look something like this:
.
├── app
│   ├── control
│   ├── model
│   └── view
├── assets
│   └── vuejs
└── public
    ├── css
    ├── images
    └── js
here has an example using with symfony and here also.
With Larable.
But if your php application is separated from vuejs only by communicating by a restful api for example, it would be best to leave them totally separate, that way:
.
├── backend
│   ├── app
│   │   ├── control
│   │   ├── model
│   │   └── view
│   └── public
│       ├── css
│       ├── images
│       └── js
└── frontend
    └── vuejs
							
							
						 
Ta using some framework in php?
– fajuchem
No, php pure msm.
– Glaydson Saragoça