Please help new user -- errors with LitElement example

[David Arsenault]

Hello Polymer Community:

New user here having a bit of trouble with lit-element with TS, and not sure why.

I have TS setup and working fine (compiled other TS examples).

Did npm install lit-element per Getting Started page.

https://lit-element.polymer-project.org/guide/start

Trying the TS example under the section: "Use LitElement TypeScript decorators" and getting all kinds of bad happening.

tsc my-element.ts results in complete fail:

my-element.ts:14:14 - error TS1219: Experimental support for decorators is a feature that is subject to change in a future release. Set the 'experimentalDecorators' option in your 'tsconfig' or 'jsconfig' to remove this warning.

14 export class MyElement extends LitElement {

                ~~~~~~~~~

my-element.ts:20:3 - error TS1219: Experimental support for decorators is a feature that is subject to change in a future release. Set the 'experimentalDecorators' option in your 'tsconfig' or 'jsconfig' to remove this warning.

20   foo = 'foo';

     ~~~

node_modules/lit-element/lib/updating-element.d.ts:102:38 - error TS2583: Cannot find name 'Map'. Do you need to change your target library? Try changing the `lib` compiler option to es2015 or later.

102 export declare type PropertyValues = Map<PropertyKey, unknown>;

                                         ~~~

node_modules/lit-html/lib/parts.d.ts:18:63 - error TS2304: Cannot find name 'Iterable'.

18 export declare const isIterable: (value: unknown) => value is Iterable<unknown>;

                                                                 ~~~~~~~~

node_modules/lit-html/lib/render.d.ts:16:29 - error TS2583: Cannot find name 'WeakMap'. Do you need to change your target library? Try changing the `lib` compiler option to es2015 or later.

16 export declare const parts: WeakMap<Node, NodePart>;

                               ~~~~~~~

node_modules/lit-html/lib/template-factory.d.ts:56:28 - error TS2583: Cannot find name 'WeakMap'. Do you need to change your target library? Try changing the `lib` compiler option to es2015 or later.

56     readonly stringsArray: WeakMap<TemplateStringsArray, Template>;

                              ~~~~~~~

node_modules/lit-html/lib/template-factory.d.ts:57:25 - error TS2583: Cannot find name 'Map'. Do you need to change your target library? Try changing the `lib` compiler option to es2015 or later.

57     readonly keyString: Map<string, Template>;

                           ~~~

node_modules/lit-html/lib/template-factory.d.ts:59:38 - error TS2583: Cannot find name 'Map'. Do you need to change your target library? Try changing the `lib` compiler option to es2015 or later.

59 export declare const templateCaches: Map<string, templateCache>;

                                        ~~~

Found 8 errors.

I have no idea how to press forward and really want to work with web components and TS for a new project.

My tsconfig.json is:

{

"compilerOptions": {

"target": "es6",

"module": "es6"

}

}

I have also tried with no tsconfig file. Same results.

Please kind people help point me in the right direction.

Thank you.

David