♻️ Migrate most of #core to pass TS typechecking (#37141)

* Pass tsc for #core/mode

* Pass tsc for #core/constants

* Pass tsc for #core/types

* Pass tsc for #core/data-structures

* Pass tsc for #core/error

* Pass tsc for #core/document

* Pass tsc for #core/window

* Rebase/merge fix

* Fix stragglers

Pass tsc for #core/dom

* Pass tsc for #core/*.js

* Remove all extern files in core

* Remove ! from annotations (used by closure, implied by TS)

* Lint fixes

* Add .d.ts to lint globs

* Lint fixes

* Remove outdated AsyncInput interface decl

* Remove .d.ts from lint globs

* `readonly` syntax instead of ReadonlyArray<>

* Disable closure type-checking during presubmit.

* Lint fixes

* Lint fixes

* Enable strict null checking and fix...everything

* Rename tuple typedefs for uniqueness

* Fix type definition files

* Fix typedef location

* Fix typos and type decls ofr AMP_REPORT_ERROR

* Add missing fullscreen externs

* More fullscreen typefills

* Remove createdCallback from html-element.d.ts

* Remove comment

* Revert build-system/global.d.ts lint change

build-system/tasks/check-types.js

@@ -46,6 +46,7 @@ const getExtensionSrcPaths = () =>
 const TSC_TYPECHECK_TARGETS = {
   'compiler': 'src/compiler',
   'carousel': 'extensions/amp-carousel/0.1',
+  'core': 'src/core',
 };
 
 /**
@@ -73,18 +74,10 @@ const CLOSURE_TYPE_CHECK_TARGETS = {
     srcGlobs: ['src/amp-story-player/**/*.js'],
     warningLevel: 'QUIET',
   },
-  'src-core': CORE_SRCS_GLOBS,
-  'src-experiments': ['src/experiments/**/*.js', ...CORE_SRCS_GLOBS],
   'src-inabox': {
     srcGlobs: ['src/inabox/**/*.js'],
     warningLevel: 'QUIET',
   },
-  'src-polyfills': [
-    'src/polyfills/**/*.js',
-    // Exclude fetch its dependencies are cleaned up/extracted to core.
-    '!src/polyfills/fetch.js',
-    ...CORE_SRCS_GLOBS,
-  ],
   'src-preact': {
     srcGlobs: ['src/preact/**/*.js', ...CORE_SRCS_GLOBS],
     warningLevel: 'QUIET',

build-system/test-configs/forbidden-terms.js

@@ -632,7 +632,6 @@ const forbiddenTermsGlobal = {
       'build-system/tasks/default-task.js',
       'build-system/tasks/dist.js',
       'src/config.js',
-      'src/core/window/window.extern.js',
       'src/experiments/index.js',
       'src/experiments/shame.extern.js',
       'src/mode.js',

src/compiler/types.d.ts

@@ -11,7 +11,7 @@ import {TreeProto, NodeProto} from '@ampproject/bento-compiler';
  * The return value is set to *, so that we may optionally return any DOM nodes
  * created during a client-side render. These nodes are often needed for ivars.
  */
-export type BuildDom = (Element) => void;
+export type BuildDom = (el: Element) => void;
 
 /**
  * Contains component versioning data via a map from tagName --> version.

src/core/3p-frame-messaging.js

@@ -55,11 +55,11 @@ export const MessageType_Enum = {
 
 /**
  * Listens for the specified event on the element.
- * @param {!EventTarget} element
+ * @param {EventTarget} element
  * @param {string} eventType
- * @param {function(!Event)} listener
+ * @param {function(Event):void} listener
  * @param {Object=} opt_evtListenerOpts
- * @return {!UnlistenDef}
+ * @return {UnlistenCallback}
  */
 export function listen(element, eventType, listener, opt_evtListenerOpts) {
   return internalListenImplementation(

src/core/amp-config.d.ts

@@ -0,0 +1,9 @@
+export {};
+
+declare global {
+  // AMP configuration and runtime settings structure.
+  interface AmpConfigDef {
+    test?: boolean;
+    localDev?: boolean;
+  }
+}

src/core/assert.shame.d.ts

@@ -0,0 +1,7 @@
+declare module '#core/assert' {
+  function devAssert<T>(subject: T | null | undefined, msg?: string, ...any): T;
+  function userAssert<T>(subject: T | null | undefined, msg?: string, ...any): T;
+  function devAssertElement<T>(subject: T, msg?: string, ...any): HTMLElement;
+  function devAssertString<T>(subject: T, msg?: string, ...any): string;
+  function devAssertNumber<T>(subject: T, msg?: string, ...any): number;
+}

src/core/assert/index.js

@@ -1,2 +1,3 @@
+// @ts-nocheck
 export * from './dev';
 export * from './user';

src/core/constants/action-constants.js

@@ -9,7 +9,9 @@ import {devAssert} from '#core/assert';
  * The action service delegates parsing of object literals to the corresponding
  * extension (in the example above, amp-bind).
  *
- * @see ./service/action-impl.ActionInfoDef
+ * See ./service/action-impl.ActionInfoDef
+ * TODO(rcebulko): Revert to @see once type is available
+ *
  * @const {string}
  */
 export const RAW_OBJECT_ARGS_KEY = '__AMP_OBJECT_STRING__';
@@ -55,7 +57,7 @@ export const ActionTrust_Enum = {
 };
 
 /**
- * @param {!ActionTrust_Enum} actionTrust
+ * @param {ActionTrust_Enum} actionTrust
  * @return {string}
  */
 export function actionTrustToString(actionTrust) {

src/core/constants/async-input.d.ts

@@ -0,0 +1,17 @@
+/**
+ * Interface for all AMP Async Input Elements.
+ * enforces the overridable function, getValue().
+ * Async Input should be implemented
+ * by components like AMP form, to async request
+ * a value from a component, and then be used for
+ * some other action. For examples, this can be used
+ * by reCAPTCHA to request tokens for the form.
+ *
+ * NOTE: Elements that implemented AsyncInput must
+ * Also add and follow the other exported constants.
+ * See amp-recaptcha-input as an example.
+ */
+export interface AsyncInput {
+  // Called to get the asynchronous value of an AsyncInput field.
+  getValue: () => Promise<string>;
+}

src/core/constants/async-input.js

@@ -1,27 +1,3 @@
-/**
- * Interface for all AMP Async Input Elements.
- * enforces the overridable function, getValue().
- * Async Input should be implemented
- * by components like AMP form, to async request
- * a value from a component, and then be used for
- * some other action. For examples, this can be used
- * by reCAPTCHA to request tokens for the form.
- *
- * NOTE: Elements that implemented AsyncInput must
- * Also add and follow the other exported constants.
- * See amp-recaptcha-input as an example.
- *
- * @interface
- */
-export class AsyncInput {
-  /**
-   * Called to get the asynchronous value of an
-   * AsyncInput field.
-   * @return {!Promise<string>}
-   */
-  getValue() {}
-}
-
 /**
  * Attributes
  *

src/core/constants/loading-instructions.js

@@ -31,15 +31,15 @@ export const Loading_Enum = {
   UNLOAD: 'unload',
 };
 
-/** @const {!Array<!Loading_Enum>} */
+/** @const {Array<Loading_Enum>} */
 const ORDER = [
   Loading_Enum.AUTO,
   Loading_Enum.LAZY,
   Loading_Enum.EAGER,
   Loading_Enum.UNLOAD,
 ];
 
-/** @const {!Object<string, number>} */
+/** @const {Object<string, number>} */
 const MAP = {
   [Loading_Enum.AUTO]: 0,
   [Loading_Enum.LAZY]: 1,
@@ -51,9 +51,9 @@ const MAP = {
  * Returns the loading instruction with a higher priority. The priority
  * order is auto -> lazy -> eager -> unload.
  *
- * @param {!Loading_Enum|string} v1
- * @param {!Loading_Enum|string} v2
- * @return {!Loading_Enum}
+ * @param {Loading_Enum|string} v1
+ * @param {Loading_Enum|string} v2
+ * @return {Loading_Enum}
  */
 export function reducer(v1, v2) {
   const ordinal1 = MAP[v1] || 0;

src/core/data-structures/curve.js

@@ -20,7 +20,7 @@ export let CurveDef;
  * @param {number} y1 Y coordinate of the first control point.
  * @param {number} x2 X coordinate of the second control point.
  * @param {number} y2 Y coordinate of the second control point.
- * @return {!CurveDef}
+ * @return {CurveDef}
  */
 export function bezierCurve(x1, y1, x2, y2) {
   return (xVal) =>
@@ -198,57 +198,57 @@ class Bezier {
 /**
  * A collection of common curves.
  * See https://developer.mozilla.org/en-US/docs/Web/CSS/timing-function
- * @enum {!CurveDef}
+ * @enum {CurveDef}
  */
 export const Curves_Enum = {
   /**
    * linear
-   * @param {!NormTimeDef} xVal
-   * @return {!NormTimeDef}
+   * @param {NormTimeDef} xVal
+   * @return {NormTimeDef}
    */
   LINEAR(xVal) {
     return xVal;
   },
 
   /**
    * ease
-   * @param {!NormTimeDef} xVal
-   * @return {!NormTimeDef}
+   * @param {NormTimeDef} xVal
+   * @return {NormTimeDef}
    */
   EASE(xVal) {
     return Bezier.solveYValueFromXValue(xVal, 0, 0, 0.25, 0.1, 0.25, 1.0, 1, 1);
   },
 
   /**
    * ease-in: slow out, fast in
-   * @param {!NormTimeDef} xVal
-   * @return {!NormTimeDef}
+   * @param {NormTimeDef} xVal
+   * @return {NormTimeDef}
    */
   EASE_IN(xVal) {
     return Bezier.solveYValueFromXValue(xVal, 0, 0, 0.42, 0.0, 1.0, 1.0, 1, 1);
   },
 
   /**
    * ease-out: fast out, slow in
-   * @param {!NormTimeDef} xVal
-   * @return {!NormTimeDef}
+   * @param {NormTimeDef} xVal
+   * @return {NormTimeDef}
    */
   EASE_OUT(xVal) {
     return Bezier.solveYValueFromXValue(xVal, 0, 0, 0.0, 0.0, 0.58, 1.0, 1, 1);
   },
 
   /**
    * ease-in-out
-   * @param {!NormTimeDef} xVal
-   * @return {!NormTimeDef}
+   * @param {NormTimeDef} xVal
+   * @return {NormTimeDef}
    */
   EASE_IN_OUT(xVal) {
     return Bezier.solveYValueFromXValue(xVal, 0, 0, 0.42, 0.0, 0.58, 1.0, 1, 1);
   },
 };
 
 /**
- * @const {!Object<string, !CurveDef>}
+ * @const {Object<string, CurveDef>}
  */
 const NAME_MAP = {
   'linear': Curves_Enum.LINEAR,
@@ -287,5 +287,5 @@ export function getCurve(curve) {
     }
     return NAME_MAP[curve];
   }
-  return /** @type {!CurveDef} */ (curve);
+  return /** @type {CurveDef} */ (curve);
 }

src/core/data-structures/dom-based-weakref.js

@@ -8,7 +8,7 @@
  */
 export class DomBasedWeakRef {
   /**
-   * @param {!Window} win
+   * @param {Window} win
    * @param {string} id
    * @package
    */
@@ -21,9 +21,9 @@ export class DomBasedWeakRef {
   /**
    * Returns a WeakRef. Uses this implementation if the real WeakRef class
    * is not available.
-   * @param {!Window} win
-   * @param {!Element} element
-   * @return {!WeakRef<!Element>|!DomBasedWeakRef<!Element>}
+   * @param {Window} win
+   * @param {Element} element
+   * @return {WeakRef<Element>|DomBasedWeakRef}
    */
   static make(win, element) {
     if (win.WeakRef) {
@@ -36,7 +36,7 @@ export class DomBasedWeakRef {
     return new DomBasedWeakRef(win, element.id);
   }
 
-  /** @return {!Element|undefined} */
+  /** @return {Element|undefined} */
   deref() {
     return this.win.document.getElementById(this.id_) || undefined;
   }

src/core/data-structures/finite-state-machine.js

@@ -18,7 +18,7 @@ export class FiniteStateMachine {
     /**
      * Callbacks that are invoked when transitioning from an old state
      * to the new.
-     * @private {Object<string, function()>}
+     * @private {Object<string, function():void>}
      */
     this.transitions_ = map();
   }
@@ -28,7 +28,7 @@ export class FiniteStateMachine {
    * transitions to the newState.
    * @param {STATE} oldState
    * @param {STATE} newState
-   * @param {function()} callback
+   * @param {function():void} callback
    */
   addTransition(oldState, newState, callback) {
     const transition = this.statesToTransition_(oldState, newState);

src/core/data-structures/lru-cache.js

@@ -20,7 +20,7 @@ export class LruCache {
      */
     this.access_ = 0;
 
-    /** @private {!Object<(number|string), {payload: T, access: number}>} */
+    /** @private {Object<(number|string), {payload: T, access: number}>} */
     this.cache_ = map();
   }
 
@@ -36,7 +36,7 @@ export class LruCache {
 
   /**
    * @param {number|string} key
-   * @return {T} The cached payload.
+   * @return {T|undefined} The cached payload.
    */
   get(key) {
     const cacheable = this.cache_[key];

src/core/data-structures/observable.js

@@ -10,14 +10,14 @@ export class Observable {
    * Creates an instance of Observable.
    */
   constructor() {
-    /** @type {?Array<function(TYPE)>} */
+    /** @type {?Array<function(TYPE=):void>} */
     this.handlers_ = null;
   }
 
   /**
    * Adds the observer to this instance.
-   * @param {function(TYPE)} handler Observer's handler.
-   * @return {!UnlistenDef}
+   * @param {function(TYPE=):void} handler Observer's handler.
+   * @return {UnlistenCallback}
    */
   add(handler) {
     if (!this.handlers_) {
@@ -31,7 +31,7 @@ export class Observable {
 
   /**
    * Removes the observer from this instance.
-   * @param {function(TYPE)} handler Observer's instance.
+   * @param {function(TYPE=):void} handler Observer's instance.
    */
   remove(handler) {
     if (!this.handlers_) {

src/core/data-structures/priority-queue.js

@@ -13,7 +13,7 @@ export class PriorityQueue {
 
   /**
    * Returns the max priority item without dequeueing it.
-   * @return {T}
+   * @return {?T}
    */
   peek() {
     const l = this.length;
@@ -67,7 +67,7 @@ export class PriorityQueue {
   }
 
   /**
-   * @param {function(T)} callback
+   * @param {function(T):any} callback
    */
   forEach(callback) {
     let index = this.length;
@@ -79,7 +79,7 @@ export class PriorityQueue {
   /**
    * Dequeues the max priority item.
    * Items with the same priority are dequeued in FIFO order.
-   * @return {T}
+   * @return {?T}
    */
   dequeue() {
     if (!this.length) {