feat: add helper function for correct TypeScript typing of yielded Promises

Author: n1ru4l

src/use-async-effect.spec.tsx

@@ -391,3 +391,20 @@ it("calls latest generator reference upon dependency change", async done => {
   unmount();
   done();
 });
+
+it("interfers the correct type with the typing helper", async done => {
+  const TestComponent: React.FC<{}> = () => {
+    useAsyncEffect(function*(setErrorHandler, cast) {
+      const a = yield* cast(
+        Promise.resolve({ type: "FOO" as "FOO", value: 1 })
+      );
+      expect(a).toEqual({ type: "FOO", value: 1 });
+    }, []);
+    return null;
+  };
+
+  const { unmount } = render(<TestComponent />);
+  await Promise.resolve();
+  unmount();
+  done();
+});

src/use-async-effect.ts

@@ -1,16 +1,26 @@
 import { useEffect, useRef } from "react";
 
-// eslint-disable-next-line  @typescript-eslint/no-empty-function
-const noop = () => { };
+// eslint-disable-next-line @typescript-eslint/no-empty-function
+const noop = () => {};
+
+type GeneratorReturnValueType = void | (() => void);
+
+function* cast<T>(input: Promise<T>): Generator<Promise<T>, T> {
+  // eslint-disable-next-line
+  // @ts-ignore
+  return yield input;
+}
+
+type ThenArg<T> = T extends PromiseLike<infer U> ? U : T;
 
 export const useAsyncEffect = (
   createGenerator: (
     setCancelHandler: (
       onCancel?: null | (() => void),
       onCancelError?: null | ((err: Error) => void)
-    ) => void
-  ) => // eslint-disable-next-line @typescript-eslint/no-explicit-any
-    Iterator<any, any, any>,
+    ) => void,
+    cast: <T>(promise: Promise<T>) => Generator<Promise<T>, T>
+  ) => Iterator<unknown, GeneratorReturnValueType>,
   deps: React.DependencyList
 ) => {
   const generatorRef = useRef(createGenerator);
@@ -27,7 +37,8 @@ export const useAsyncEffect = (
       (cancelHandler, cancelErrorHandler) => {
         onCancel = cancelHandler || noop;
         onCancelError = cancelErrorHandler || noop;
-      }
+      },
+      cast
     );
     let cleanupHandler = noop;
 

tsconfig.json

@@ -4,7 +4,7 @@
     "esModuleInterop": true,
     "declaration": true,
     "skipLibCheck": true,
+    "downlevelIteration": true,
     "lib": ["ESNext", "DOM"]
-  },
-  "exclude": ["**/*.spec.ts", "**/*.spec.tsx"]
+  }
 }

yarn.lock

@@ -2141,7 +2141,7 @@ debug@^3.1.0:
   dependencies:
     ms "^2.1.1"
 
-debuglog@*, debuglog@^1.0.1:
+debuglog@^1.0.1:
   version "1.0.1"
   resolved "https://registry.yarnpkg.com/debuglog/-/debuglog-1.0.1.tgz#aa24ffb9ac3df9a2351837cfb2d279360cd78492"
   integrity sha1-qiT/uaw9+aI1GDfPstJ5NgzXhJI=
@@ -3550,7 +3550,7 @@ import-local@^3.0.2:
     pkg-dir "^4.2.0"
     resolve-cwd "^3.0.0"
 
-imurmurhash@*, imurmurhash@^0.1.4:
+imurmurhash@^0.1.4:
   version "0.1.4"
   resolved "https://registry.yarnpkg.com/imurmurhash/-/imurmurhash-0.1.4.tgz#9218b9b2b928a238b13dc4fb6b6d576f231453ea"
   integrity sha1-khi5srkoojixPcT7a21XbyMUU+o=
@@ -4838,11 +4838,6 @@ lockfile@^1.0.4:
   dependencies:
     signal-exit "^3.0.2"
 
-lodash._baseindexof@*:
-  version "3.1.0"
-  resolved "https://registry.yarnpkg.com/lodash._baseindexof/-/lodash._baseindexof-3.1.0.tgz#fe52b53a1c6761e42618d654e4a25789ed61822c"
-  integrity sha1-/lK1OhxnYeQmGNZU5KJXie1hgiw=
-
 lodash._baseuniq@~4.6.0:
   version "4.6.0"
   resolved "https://registry.yarnpkg.com/lodash._baseuniq/-/lodash._baseuniq-4.6.0.tgz#0ebb44e456814af7905c6212fa2c9b2d51b841e8"
@@ -4851,33 +4846,11 @@ lodash._baseuniq@~4.6.0:
     lodash._createset "~4.0.0"
     lodash._root "~3.0.0"
 
-lodash._bindcallback@*:
-  version "3.0.1"
-  resolved "https://registry.yarnpkg.com/lodash._bindcallback/-/lodash._bindcallback-3.0.1.tgz#e531c27644cf8b57a99e17ed95b35c748789392e"
-  integrity sha1-5THCdkTPi1epnhftlbNcdIeJOS4=
-
-lodash._cacheindexof@*:
-  version "3.0.2"
-  resolved "https://registry.yarnpkg.com/lodash._cacheindexof/-/lodash._cacheindexof-3.0.2.tgz#3dc69ac82498d2ee5e3ce56091bafd2adc7bde92"
-  integrity sha1-PcaayCSY0u5ePOVgkbr9Ktx73pI=
-
-lodash._createcache@*:
-  version "3.1.2"
-  resolved "https://registry.yarnpkg.com/lodash._createcache/-/lodash._createcache-3.1.2.tgz#56d6a064017625e79ebca6b8018e17440bdcf093"
-  integrity sha1-VtagZAF2JeeevKa4AY4XRAvc8JM=
-  dependencies:
-    lodash._getnative "^3.0.0"
-
 lodash._createset@~4.0.0:
   version "4.0.3"
   resolved "https://registry.yarnpkg.com/lodash._createset/-/lodash._createset-4.0.3.tgz#0f4659fbb09d75194fa9e2b88a6644d363c9fe26"
   integrity sha1-D0ZZ+7CddRlPqeK4imZE02PJ/iY=
 
-lodash._getnative@*, lodash._getnative@^3.0.0:
-  version "3.9.1"
-  resolved "https://registry.yarnpkg.com/lodash._getnative/-/lodash._getnative-3.9.1.tgz#570bc7dede46d61cdcde687d65d3eecbaa3aaff5"
-  integrity sha1-VwvH3t5G1hzc3mh9ZdPuy6o6r/U=
-
 lodash._root@~3.0.0:
   version "3.0.1"
   resolved "https://registry.yarnpkg.com/lodash._root/-/lodash._root-3.0.1.tgz#fba1c4524c19ee9a5f8136b4609f017cf4ded692"
@@ -4918,11 +4891,6 @@ lodash.memoize@4.x:
   resolved "https://registry.yarnpkg.com/lodash.memoize/-/lodash.memoize-4.1.2.tgz#bcc6c49a42a2840ed997f323eada5ecd182e0bfe"
   integrity sha1-vMbEmkKihA7Zl/Mj6tpezRguC/4=
 
-lodash.restparam@*:
-  version "3.6.1"
-  resolved "https://registry.yarnpkg.com/lodash.restparam/-/lodash.restparam-3.6.1.tgz#936a4e309ef330a7645ed4145986c85ae5b20805"
-  integrity sha1-k2pOMJ7zMKdkXtQUWYbIWuWyCAU=
-
 lodash.set@^4.3.2:
   version "4.3.2"
   resolved "https://registry.yarnpkg.com/lodash.set/-/lodash.set-4.3.2.tgz#d8757b1da807dde24816b0d6a84bea1a76230b23"
@@ -5633,7 +5601,6 @@ npm@^6.10.3:
     cmd-shim "^3.0.3"
     columnify "~1.5.4"
     config-chain "^1.1.12"
-    debuglog "*"
     detect-indent "~5.0.0"
     detect-newline "^2.1.0"
     dezalgo "~1.0.3"
@@ -5648,7 +5615,6 @@ npm@^6.10.3:
     has-unicode "~2.0.1"
     hosted-git-info "^2.8.5"
     iferr "^1.0.2"
-    imurmurhash "*"
     infer-owner "^1.0.4"
     inflight "~1.0.6"
     inherits "^2.0.4"
@@ -5667,14 +5633,8 @@ npm@^6.10.3:
     libnpx "^10.2.0"
     lock-verify "^2.1.0"
     lockfile "^1.0.4"
-    lodash._baseindexof "*"
     lodash._baseuniq "~4.6.0"
-    lodash._bindcallback "*"
-    lodash._cacheindexof "*"
-    lodash._createcache "*"
-    lodash._getnative "*"
     lodash.clonedeep "~4.5.0"
-    lodash.restparam "*"
     lodash.union "~4.6.0"
     lodash.uniq "~4.5.0"
     lodash.without "~4.4.0"