pxt-calliope/sim/tsconfig.json

{
    "compilerOptions": {
        "target": "es5",
        "noImplicitAny": true,
        "noImplicitReturns": true,
        "declaration": true,
        "out": "../built/sim.js",
        "rootDir": ".",
        "newLine": "LF",
        "sourceMap": false,
        "lib": ["dom", "dom.iterable", "scripthost", "es6"],
        "types": ["jquery", "bluebird"],
        "typeRoots": ["../node_modules/@types"]
    }
}