How to change the standard for Typescript?

Question

typescript

Installed npm install typescript in the folder. The folder contains the following files:
1) test.ts

const str:string = "Hello TS !"
console.log(str)

2) test.js

var str = "Hello TS !";
console.log(str);

3) tsconfig.json

{
    "compilerOptions": {
      "target": "ES2020",
      "module": "commonjs",
      "strict": true,
      "esModuleInterop": true,
      "skipLibCheck": true,
      "forceConsistentCasingInFileNames": true
    },
    "$schema": "https://json.schemastore.org/tsconfig",
    "display": "Recommended"
  }

4) node_modules
test.js was compiled with test.ts via command "tsc test.ts" The
question is, why is str variable defined via var ? How to make it so that it would be const

Answer 1

Compile a project, not a single file.
When you call tsc test.ts, TS does not read tsconfig.json, but uses the default settings.
So just call tsc.
Or explicitly specify options on the command linetsc --target ES2020 test.ts