Difference in the 'lib' property in tsconfig.json between es6 and es2017?

ecmascript-2017, ecmascript-6, typescript, typescript-typings, typescript2.0

Solution

After some digging and comparing through the `lib` folder on the Typescript GitHub I have found that, using `es6` in the `lib` property in the `compilerOptions` corresponds to the code found in these references:

/// <reference path="lib.es2015.core.d.ts" />
/// <reference path="lib.es2015.collection.d.ts" />
/// <reference path="lib.es2015.generator.d.ts" />
/// <reference path="lib.es2015.iterable.d.ts" />
/// <reference path="lib.es2015.promise.d.ts" />
/// <reference path="lib.es2015.proxy.d.ts" />
/// <reference path="lib.es2015.reflect.d.ts" />
/// <reference path="lib.es2015.symbol.d.ts" />
/// <reference path="lib.es2015.symbol.wellknown.d.ts" />
/// <reference path="lib.es5.d.ts" />
/// <reference path="lib.dom.d.ts" />
/// <reference path="lib.scripthost.d.ts.d.ts" />
/// <reference path="lib.dom.iterable.d.ts" />

so to answer my question, to correctly cover all the contents of `es6` with `es2017` that section of the tsconfig.json should look like this:

{
  ...
  "compilerOptions": {
    ...
    "lib": ["es2017", "dom", "dom.iterable", "scripthost"]
  },
  ...
  }
}

Problem

I've been researching what the possible values of the `lib` property mean in the `compilerOptions` found within the `tsconfig.json` file. I found on the Typescript GitHub page the relevant `d.ts` files corresponding to those values and apparently by using `ES2017` the following ES features are included: ``` /// <reference path="lib.es2016.d.ts" /> /// <reference path="lib.es2017.object.d.ts" /> /// <reference path="lib.es2017.sharedmemory.d.ts" /> /// <reference path="lib.es2017.string.d.ts" /> /// <reference path="lib.es2015.d.ts" /> /// <reference path="lib.es2016.array.include.d.ts" /> /// <reference path="lib.es2015.core.d.ts" /> /// <reference path="lib.es2015.collection.d.ts" /> /// <reference path="lib.es2015.generator.d.ts" /> /// <reference path="lib.es2015.iterable.d.ts" /> /// <reference path="lib.es2015.promise.d.ts" /> /// <reference path="lib.es2015.proxy.d.ts" /> /// <reference path="lib.es2015.reflect.d.ts" /> /// <reference path="lib.es2015.symbol.d.ts" /> /// <reference path="lib.es2015.symbol.wellknown.d.ts" /> /// <reference path="lib.es5.d.ts" /> ``` But apparently ES6 is not included and has it's own file that doesn't reference anything. My question is, if anybody knows, is it safe to assume that by using `es2017` I cover all the `es6` functionality (from a typings perspective) or should that be included separately in the `lib` option? For example, like this: ``` { ... "compilerOptions": { ... "lib": ["es2017", "dom"] }, ... } } ``` OR this: ``` { ... "compilerOptions": { ... "lib": ["es2017", "es6", "dom"] }, ... } } ```

Original source