[helpers TS conversion] New decorators (#16540)

* New decorators Helpers

* review

packages/babel-helpers/src/helpers/applyDecs2311.ts

@@ -1,6 +1,8 @@
 /* @minVersion 7.24.0 */
 /* @mangleFns */
 
+/* eslint-disable @typescript-eslint/no-unnecessary-type-assertion -- `typescript-eslint` complains when using `!` */
+
 import checkInRHS from "./checkInRHS.ts";
 import setFunctionName from "./setFunctionName.ts";
 import toPropertyKey from "./toPropertyKey.ts";
@@ -266,14 +268,14 @@ export default /* @no-mangle */ function applyDecs2311(
     hasPrivateBrand?: Function,
   ) {
     function assertInstanceIfPrivate(target: any) {
-      if (!hasPrivateBrand(target)) {
+      if (!hasPrivateBrand!(target)) {
         throw new TypeError(
           "Attempted to access private element on non-instance",
         );
       }
     }
 
-    var decs = [].concat(decInfo[0]),
+    var decs = ([] as Function[]).concat(decInfo[0]),
       decVal = decInfo[3],
       isClass = !ret;
 
@@ -314,13 +316,13 @@ export default /* @no-mangle */ function applyDecs2311(
           desc = {
             get: setFunctionName(
               function (this: any) {
-                return decVal(this);
+                return decVal!(this);
               },
               name,
               "get",
             ),
             set: function (this: any, value: any) {
-              decInfo[4](this, value);
+              decInfo[4]!(this, value);
             },
           };
         } else {
@@ -331,11 +333,11 @@ export default /* @no-mangle */ function applyDecs2311(
           setFunctionName(desc[key], name, isMethod ? "" : key);
         }
       } else if (!isField) {
-        desc = Object.getOwnPropertyDescriptor(Class, name);
+        desc = Object.getOwnPropertyDescriptor(Class, name)!;
       }
 
       if (!isField && !isPrivate) {
-        _ = existingNonFields[+isStatic][name];
+        _ = existingNonFields[+isStatic!][name];
         // flag is 1, 3, or 4; kind is 0, 1, 2, 3, or 4
         // flag ^ kind is 7 if and only if one of them is 3 and the other one is 4.
         if (_ && (_ ^ kind) !== 7) {
@@ -347,7 +349,7 @@ export default /* @no-mangle */ function applyDecs2311(
         }
         // We use PROP_KIND.ACCESSOR to mark a name as "fully used":
         // either a get/set pair, or a non-getter/setter.
-        existingNonFields[+isStatic][name] =
+        existingNonFields[+isStatic!][name] =
           kind < PROP_KIND.GETTER
             ? PROP_KIND.ACCESSOR
             : (kind as PROP_KIND.GETTER | PROP_KIND.SETTER);
@@ -426,24 +428,24 @@ export default /* @no-mangle */ function applyDecs2311(
           decThis,
           isAccessor
             ? {
-                get: desc.get,
-                set: desc.set,
+                get: desc!.get,
+                set: desc!.set,
               }
-            : desc[key],
+            : desc![key!],
           ctx,
         );
         decoratorFinishedRef.v = 1;
 
         if (isAccessor) {
           if (typeof newValue === "object" && newValue) {
             if ((_ = assertCallable(newValue.get, "accessor.get"))) {
-              desc.get = _;
+              desc!.get = _;
             }
             if ((_ = assertCallable(newValue.set, "accessor.set"))) {
-              desc.set = _;
+              desc!.set = _;
             }
             if ((_ = assertCallable(newValue.init, "accessor.init"))) {
-              init.unshift(_);
+              init!.unshift(_);
             }
           } else if (newValue !== void 0) {
             throw new TypeError(
@@ -458,19 +460,19 @@ export default /* @no-mangle */ function applyDecs2311(
           )
         ) {
           if (isField) {
-            init.unshift(newValue);
+            init!.unshift(newValue);
           } else {
-            desc[key] = newValue;
+            desc![key!] = newValue;
           }
         }
       }
     }
 
     // isField || isAccessor
     if (kind < PROP_KIND.METHOD) {
-      ret.push(
+      ret!.push(
         // init
-        createRunInitializers(init, isStatic, 1),
+        createRunInitializers(init!, isStatic, 1),
         // init_extra
         createRunInitializers(initializers, isStatic, 0),
       );
@@ -480,22 +482,22 @@ export default /* @no-mangle */ function applyDecs2311(
       if (isPrivate) {
         if (isAccessor) {
           // get and set should be returned before init_extra
-          ret.splice(
+          ret!.splice(
             -1,
             0,
-            _bindPropCall("get", isStatic),
-            _bindPropCall("set", isStatic),
+            _bindPropCall("get", isStatic!),
+            _bindPropCall("set", isStatic!),
           );
         } else {
-          ret.push(
+          ret!.push(
             isMethod
-              ? desc[key]
+              ? desc![key!]
               : // Equivalent to `Function.call`, just to reduce code size
-                assertCallable.call.bind(desc[key]),
+                assertCallable.call.bind(desc![key!]),
           );
         }
       } else {
-        defineProperty(Class, name, desc);
+        defineProperty(Class, name, desc!);
       }
     }
     return newValue;
@@ -520,7 +522,7 @@ export default /* @no-mangle */ function applyDecs2311(
       for (var i = 0; i < memberDecs.length; i++) {
         var decInfo = memberDecs[i];
 
-        var kind = decInfo[1];
+        var kind = decInfo[1]!;
         var kindOnly: PROP_KIND = kind & PROP_KIND.KIND_MASK;
         if (
           // eslint-disable-next-line @typescript-eslint/no-unsafe-enum-comparison, eqeqeq
@@ -565,8 +567,8 @@ export default /* @no-mangle */ function applyDecs2311(
     applyMemberDecsOfKind(PROP_KIND.STATIC, 1);
     applyMemberDecsOfKind(0, 1);
 
-    pushInitializers(protoInitializers);
-    pushInitializers(staticInitializers);
+    pushInitializers(protoInitializers!);
+    pushInitializers(staticInitializers!);
     return ret;
   }
 

packages/babel-helpers/src/helpers/defineAccessor.ts

@@ -0,0 +1,12 @@
+/* @minVersion 7.20.7 */
+
+export default function _defineAccessor<Type extends "get" | "set">(
+  type: Type,
+  obj: any,
+  key: string | symbol,
+  fn: PropertyDescriptor[Type],
+) {
+  var desc: PropertyDescriptor = { configurable: true, enumerable: true };
+  desc[type] = fn;
+  return Object.defineProperty(obj, key, desc);
+}

packages/babel-helpers/src/helpers/identity.ts

@@ -0,0 +1,5 @@
+/* @minVersion 7.17.0 */
+
+export default function _identity<T>(x: T) {
+  return x;
+}

packages/babel-helpers/src/helpers/setFunctionName.ts

@@ -7,7 +7,8 @@ export default function setFunctionName<T extends Function>(
   prefix?: string,
 ): T {
   if (typeof name === "symbol") {
-    name = name.description;
+    // Here `undefined` is possible, we check for it in the next line.
+    name = name.description!;
     name = name ? "[" + name + "]" : "";
   }
   // In some older browsers .name was non-configurable, here we catch any

packages/babel-helpers/src/helpers/tsconfig.json

@@ -2,7 +2,7 @@
   "compilerOptions": {
     "rootDir": ".",
     "target": "ESNext",
-    "module": "preserve",
+    "module": "Preserve",
     "lib": ["ESNext"],
     "declaration": false,
     "noEmit": true,
@@ -13,10 +13,5 @@
     "strict": true
   },
   "include": ["./*.ts"],
-  "exclude": [
-    "./applyDecs2305.ts",
-    "./applyDecs2311.ts",
-    "./construct.ts",
-    "./setFunctionName.ts"
-  ]
+  "exclude": ["./applyDecs2305.ts", "./construct.ts", "./usingCtx.ts"]
 }

tsconfig.base.json

@@ -3,7 +3,7 @@
     "composite": true,
     "rootDir": ".",
     "target": "ESNext",
-    "module": "preserve",
+    "module": "Preserve",
     "lib": ["ESNext"],
     "declaration": true,
     "declarationMap": true,