How to delete compiled JS files from previous typescript(.ts) files?

Question

I am following Angular 2 quick start tutorial. Following is my folder structure -

├── gulpfile.js
├── index.html
├── js
|   ├── app.component.js
|   └── boot.js
├── source
|   ├── app.component.ts
|   └── boot.ts
├── node_modules
    ├── module 1
    └── module 2

My typescript files are in source/ directory. I'm compiling it to js/ directory. I'm using gulp-typescript.

The problem is when I, for example, rename the file boot.ts to bootstrap.ts and compile again, corresponding bootstrap.js file is created but the old boot.js file still remains in the js/ directory.

Now the folder structure looks like following-

├── gulpfile.js
├── index.html
├── js
|   ├── app.component.js
|   └── bootstrap.js
|   └── boot.js
├── source
|   ├── app.component.ts
|   └── bootstrap.ts
├── node_modules
    ├── module 1
    └── module 2

I want to delete this boot.js autonomically via gulp task. How to achieve this?

Answer 1

I came here seeing the title, and adding gulp into the mix was not a solution. So here is how I solved it.

Prefix your npm build script with rm -rf ./js/ &&

"scripts": {
    ...
    "build": "rm -rf ./js/ && tsc",
    ...
},

rm -rf ./js/ forcefully removes recursively all files and dirs below ./js/ doku rm in bash

&& says, if successful do the next command && in bash

Title at the time of answering: "How to delete compiled JS files from previous typescript(.ts) files?"