Basic

basic ts config

compile ts to js

tsc hello-world.ts

configuration file for ts

tsc --init

// part of tsconfig.json
{
  "compilerOptions": {
    /* Visit https://aka.ms/tsconfig to read more about this file */
    /* Language and Environment */
    ...
    "target": "ES2016",                                  /* Set the JavaScript language version for emitted JavaScript and include compatible library declarations. */

    /* Modules */
    "module": "commonjs",                                /* Specify what module code is generated. */
    "rootDir": "./src",                                  /* Specify the root folder within your source files. */

    "outDir": "./dist",                                   /* Specify an output folder for all emitted files. */
    "removeComments": true,                           /* Disable e

    /* Type Checking */
    "strict": true,                                      /* Enable all strict type-checking options. */

    "skipLibCheck": true                                 /* Skip type checking all .d.ts files. */
  }
}

so we can now just use tsc to compile all the typescript files in our project.

debug ts code

enable sourceMap option in tsconfig.json
create a launch.json file, this tells vscode how to debug this application
Add an option "preLaunchTask": "tsc: bulid - tsconfig.json"
Then we can debug. **F5 is the shortcut **

fundamental

bulid-in types

We can separate big number using _ like:

let sales: number = 123_456_789;

The any type

Don't use it

Arrays

let numbers : number[] = [1 ,2, 3]; // remove number[] it can still be infer ed

let numbers : number[] = []; // to avoid numbers being any type
numbers.forEach(n => n.XXX // it can be auto...) 

tuple

let user : [number, string] = [1, 'Mosh'] // [better keep it 2]

enum