TypeScript complains with and without lib

Question

I'm trying to add an async function in a TypeScript project. The code looks like this:

chrome.tabs.onUpdated.addListener(async (id, c, t) => { ... });

TypeScript complains:

error TS2705: An async function or method in ES5/ES3 requires the 'Promise' constructor. Make sure you have a declaration for the 'Promise' constructor or include 'ES2015' in your --lib option

When I add lib: ['es2015'] to tsconfig, TypeScript starts complaining about all calls to console.log saying that console is undefined.

Answer 1

The default libs for es5 are DOM,ES5, so if you specify es2015 you will also need to add dom explicitly as console is defined in the dom library. Sample tsconfig.json:

{
    "compilerOptions": {
        "target": "es5",
        "lib": [
            "es2015",
            "dom"
        ]
    }
}

Typescript has a modular approach to the default libraries, so you can include only what is available based on your environment.