├── public/ <-- This is where you put all your JS end css files. │ ├── one.js │ ├── two.js │ ├── three.js │ ├── x.css │ ├── y.css │ ├── z.css ...

Due to JavaScript's dynamic typing, if you add a number and a string, it will result in string concatenation instead of numerical addition. The bug.js file shows this error, and the bugSolution.js ...