Enable @typescript-eslint/no-non-null-assertion rule

.eslintrc.js

@@ -16,7 +16,7 @@ module.exports = {
         "@typescript-eslint/ban-ts-comment": "off",
         "@typescript-eslint/no-empty-function": "off",
         "@typescript-eslint/no-explicit-any": "off",
-        "@typescript-eslint/no-non-null-assertion": "off",
+        "@typescript-eslint/no-non-null-assertion": "error",
         "@typescript-eslint/no-var-requires": "off",
         "@typescript-eslint/no-unused-vars": [
           "warn",

packages/miniflare/src/http/websocket.ts

@@ -88,7 +88,8 @@ export class WebSocket extends TypedEventTarget<WebSocketEventMap> {
   }
 
   async #queuingDispatchToPair(event: ValueOf<WebSocketEventMap>) {
-    const pair = this[kPair]!;
+    const pair = this[kPair];
+    assert(pair !== undefined);
     if (pair[kAccepted]) {
       pair.dispatchEvent(event);
     } else {
@@ -183,8 +184,11 @@ export class WebSocket extends TypedEventTarget<WebSocketEventMap> {
     //     -------      | -------                         -------------
     //                  |
 
+    const pair = this[kPair];
+    assert(pair !== undefined);
+
     this[kClosedOutgoing] = true;
-    this[kPair]![kClosedIncoming] = true;
+    pair[kClosedIncoming] = true;
 
     const event = new CloseEvent("close", { code, reason });
     void this.#queuingDispatchToPair(event);

packages/miniflare/src/index.ts

@@ -696,6 +696,7 @@ export class Miniflare {
         );
       } else if (url.pathname === "/core/log") {
         // Safety of `!`: `parseInt(null)` is `NaN`
+        // eslint-disable-next-line @typescript-eslint/no-non-null-assertion
         const level = parseInt(request.headers.get(SharedHeaders.LOG_LEVEL)!);
         assert(
           LogLevel.NONE <= level && level <= LogLevel.VERBOSE,

packages/miniflare/src/workers/cache/cache.worker.ts

@@ -356,6 +356,7 @@ export class CacheObject extends MiniflareDurableObject {
     // If we know the size, avoid passing the body through a transform stream to
     // count it (trusting `workerd` to send correct value here).
     // Safety of `!`: `parseInt(null)` is `NaN`
+    // eslint-disable-next-line @typescript-eslint/no-non-null-assertion
     const contentLength = parseInt(res.headers.get("Content-Length")!);
     let sizePromise: Promise<number>;
     if (Number.isNaN(contentLength)) {

packages/miniflare/src/workers/core/entry.worker.ts

@@ -113,6 +113,8 @@ function maybeInjectLiveReload(
   }
 
   const headers = new Headers(response.headers);
+  // Safety of `!`: `parseInt(null)` is `NaN`
+  // eslint-disable-next-line @typescript-eslint/no-non-null-assertion
   const contentLength = parseInt(headers.get("content-length")!);
   if (!isNaN(contentLength)) {
     headers.set(

packages/miniflare/src/workers/kv/namespace.worker.ts

@@ -127,9 +127,10 @@ export class KVNamespaceObject extends MiniflareDurableObject {
     // Validate value size: if we know the value length, avoid passing the body
     // through a transform stream to count it (trusting `workerd` to send
     // correct value here).
-    // Safety of `!`: `parseInt(null)` is `NaN`
     let value = req.body;
     assert(value !== null);
+    // Safety of `!`: `parseInt(null)` is `NaN`
+    // eslint-disable-next-line @typescript-eslint/no-non-null-assertion
     const contentLength = parseInt(req.headers.get("Content-Length")!);
     const valueLengthHint = Number.isNaN(contentLength)
       ? undefined

packages/miniflare/src/workers/r2/bucket.worker.ts

@@ -150,6 +150,7 @@ function rangeOverlaps(a: InclusiveRange, b: InclusiveRange): boolean {
 
 async function decodeMetadata(req: Request<unknown, unknown>) {
   // Safety of `!`: `parseInt(null)` is `NaN`
+  // eslint-disable-next-line @typescript-eslint/no-non-null-assertion
   const metadataSize = parseInt(req.headers.get(R2Headers.METADATA_SIZE)!);
   if (Number.isNaN(metadataSize)) throw new InvalidMetadata();
 
@@ -1045,6 +1046,7 @@ export class R2BucketObject extends MiniflareDurableObject {
       return new Response();
     } else if (metadata.method === "put") {
       // Safety of `!`: `parseInt(null)` is `NaN`
+      // eslint-disable-next-line @typescript-eslint/no-non-null-assertion
       const contentLength = parseInt(req.headers.get("Content-Length")!);
       // `workerd` requires a known value size for R2 put requests:
       // - https://github.com/cloudflare/workerd/blob/e3479895a2ace28e4fd5f1399cea4c92291966ab/src/workerd/api/r2-rpc.c%2B%2B#L154-L156
@@ -1066,6 +1068,7 @@ export class R2BucketObject extends MiniflareDurableObject {
       return encodeJSONResult(result);
     } else if (metadata.method === "uploadPart") {
       // Safety of `!`: `parseInt(null)` is `NaN`
+      // eslint-disable-next-line @typescript-eslint/no-non-null-assertion
       const contentLength = parseInt(req.headers.get("Content-Length")!);
       // `workerd` requires a known value size for R2 put requests as above
       assert(!isNaN(contentLength));

packages/miniflare/src/workers/shared/blob.worker.ts

@@ -50,6 +50,7 @@ async function fetchSingleRange(
     // If we specified a range, but received full content, make sure the range
     // covered the full content
     // Safety of `!`: `parseInt(null)` is `NaN`
+    // eslint-disable-next-line @typescript-eslint/no-non-null-assertion
     const contentLength = parseInt(res.headers.get("Content-Length")!);
     assert(!Number.isNaN(contentLength));
     assertFullRangeRequest(range, contentLength);
@@ -120,6 +121,7 @@ async function fetchMultipleRanges(
   assert(res.ok);
 
   // Safety of `!`: `parseInt(null)` is `NaN`
+  // eslint-disable-next-line @typescript-eslint/no-non-null-assertion
   const contentLength = parseInt(res.headers.get("Content-Length")!);
   assert(!Number.isNaN(contentLength));
 

packages/miniflare/src/workers/shared/sync.ts

@@ -22,7 +22,10 @@ export class DeferredPromise<T> extends Promise<T> {
       return executor(resolve, reject);
     });
     // Cannot access `this` until after `super`
+    // Safety of `!`: callback passed to `super()` is executed immediately
+    // eslint-disable-next-line @typescript-eslint/no-non-null-assertion
     this.resolve = promiseResolve!;
+    // eslint-disable-next-line @typescript-eslint/no-non-null-assertion
     this.reject = promiseReject!;
   }
 }