Typescript- What is target in tsconfig?

Question

I am quite new to Typescript. What does Target in tsconfig.json signify?

{
  "compilerOptions": 
  {
    "sourceMap": true,
    "target": "es5",
    "module": "commonjs",
    "jsx": "react",
    "moduleResolution": "classic",
    "lib": [ "es2015", "dom",  "es2017" ]
  }
}

Answer 1

I am quite new to Typescript. What does Target in tsconfig.json signify?

target signifies which target of JavaScript should be emitted from the given TypeScript. Examples:

target:es5

()=>null will become function(){return null} as ES5 doesn't have arrow functions.

target:es6

()=>null will become ()=>null as ES6 has arrow functions.

Answer 2

Target changes the JavaScript version you are compiling to.

The options are available at https://www.typescriptlang.org/docs/handbook/compiler-options.html

In the spirit of trying to better understand how the target flag changes my code I compiled some test code to each of the different versions to have a better understanding of the differences.

https://github.com/aizatto/typescript-playground/tree/master/dist/test-async-main

I'm also keeping notes of what I should be targeting depending on what environment I am looking at

https://www.aizatto.com/notes/typescript