TS practice (practice/)

Synced from practice/. These are copies; the original folder is untouched.

• package.json
• tsconfig.json
• src/01-basics.ts
• src/02-basic.ts
• src/05-interface.ts
• src/06-type-aliases.ts
• src/07-union-inter.ts
• src/09-assertion-guards.ts
• src/10-classes.ts