Fix TypeScript compilation errors

Author: justinfagnani

.vscode/settings.json

@@ -0,0 +1,3 @@
+{
+  "typescript.tsdk": "node_modules/typescript/lib"
+}

src/lit-html.ts

@@ -313,7 +313,8 @@ export class Template {
           const attributeNameInPart =
               lastAttributeNameRegex.exec(stringForPart)![1];
           // Find the corresponding attribute
-          const attribute = attributes.getNamedItem(attributeNameInPart);
+          // TODO(justinfagnani): remove non-null assertion
+          const attribute = attributes.getNamedItem(attributeNameInPart)!;
           const stringsForAttributeValue = attribute.value.split(markerRegex);
           this.parts.push(new TemplatePart(
               'attribute',

src/test/lib/deferred.ts

@@ -18,13 +18,13 @@
  */
 export class Deferred<T> {
   readonly promise: Promise<T>;
-  readonly resolve: (value: T) => void;
-  readonly reject: (error: Error) => void;
+  resolve!: (value: T) => void;
+  reject!: (error: Error) => void;
 
   constructor() {
     this.promise = new Promise<T>((res, rej) => {
-      this.resolve! = res;
-      this.reject! = rej;
+      this.resolve = res;
+      this.reject = rej;
     });
   }
 }

src/test/lib/test-async-iterable.ts

@@ -29,7 +29,7 @@ export class TestAsyncIterable<T> implements AsyncIterable<T> {
    */
   private _nextValue: Promise<T> =
       new Promise((resolve, _) => this._resolveNextValue = resolve);
-  private _resolveNextValue: (value: T) => void;
+  private _resolveNextValue!: (value: T) => void;
 
   async * [Symbol.asyncIterator]() {
     while (true) {

tsconfig.json

@@ -7,12 +7,12 @@
     "sourceMap": true,
     "inlineSources": true,
     "outDir": "./",
-    // "rootDir": "./",                       /* Specify the root directory of input files. Use to control the output directory structure with --outDir. */
     "strict": true,
     "noUnusedLocals": true,
     "noUnusedParameters": true,
     "noImplicitReturns": true,
-    "noFallthroughCasesInSwitch": true
+    "noFallthroughCasesInSwitch": true,
+    "skipLibCheck": true
   },
   "include": [
     "src/**/*.ts"