convert @babel/helper-skip-transparent-expression-wrappers to typescript

lightmare · lightmare · commit 61b6b16af7b4 · 2021-08-05T15:10:24.000+02:00
* overload skipTransparentExprWrappers

* fixes isSimpleMemberExpression
  in @babel/plugin-proposal-optional-chaining

* use skipTransparentExprWrappers&lt;Expression&gt; instead of the NodePath
  overload where possible in @babel/plugin-proposal-optional-chaining
diff --git a/packages/babel-helper-skip-transparent-expression-wrappers/src/index.js b/packages/babel-helper-skip-transparent-expression-wrappers/src/index.js
diff --git a/packages/babel-helper-skip-transparent-expression-wrappers/src/index.ts b/packages/babel-helper-skip-transparent-expression-wrappers/src/index.ts
@@ -0,0 +1,49 @@
+import * as t from "@babel/types";
+import { NodePath } from "@babel/traverse";
+
+export type TransparentExprWrapper =
+  | t.TSAsExpression
+  | t.TSTypeAssertion
+  | t.TSNonNullExpression
+  | t.TypeCastExpression
+  | t.ParenthesizedExpression;
+
+// A transparent expression wrapper is an AST node that most plugins will wish
+// to skip, as its presence does not affect the behaviour of the code. This
+// includes expressions used for types, and extra parenthesis. For example, in
+// (a as any)(), this helper can be used to skip the TSAsExpression when
+// determining the callee.
+export function isTransparentExprWrapper(
+  node: t.Node,
+): node is TransparentExprWrapper {
+  return (
+    t.isTSAsExpression(node) ||
+    t.isTSTypeAssertion(node) ||
+    t.isTSNonNullExpression(node) ||
+    t.isTypeCastExpression(node) ||
+    t.isParenthesizedExpression(node)
+  );
+}
+
+type ExprNodeOrPath = t.Expression | NodePath<t.Expression>;
+
+export function skipTransparentExprWrappers(expr: t.Expression): t.Expression;
+
+export function skipTransparentExprWrappers(
+  expr: NodePath<t.Expression>,
+): NodePath<t.Expression>;
+
+export function skipTransparentExprWrappers(
+  expr: ExprNodeOrPath,
+): ExprNodeOrPath {
+  if (expr instanceof NodePath) {
+    while (isTransparentExprWrapper(expr.node)) {
+      expr = expr.get("expression");
+    }
+  } else {
+    while (isTransparentExprWrapper(expr)) {
+      expr = expr.expression;
+    }
+  }
+  return expr;
+}
diff --git a/packages/babel-plugin-bugfix-v8-spread-parameters-in-optional-chaining/src/util.ts b/packages/babel-plugin-bugfix-v8-spread-parameters-in-optional-chaining/src/util.ts
@@ -22,7 +22,7 @@ function matchAffectedArguments(argumentNodes) {
 export function shouldTransform(
   path: NodePath<t.OptionalMemberExpression | t.OptionalCallExpression>,
 ): boolean {
-  let optionalPath = path;
+  let optionalPath: NodePath<t.Expression> = path;
   const chains = [];
   while (
     optionalPath.isOptionalMemberExpression() ||
diff --git a/packages/babel-plugin-proposal-optional-chaining/src/transform.js b/packages/babel-plugin-proposal-optional-chaining/src/transform.js
@@ -1,8 +1,5 @@
 import { types as t, template } from "@babel/core";
-import {
-  isTransparentExprWrapper,
-  skipTransparentExprWrappers,
-} from "@babel/helper-skip-transparent-expression-wrappers";
+import { skipTransparentExprWrappers } from "@babel/helper-skip-transparent-expression-wrappers";
 import { willPathCastToBoolean, findOutermostTransparentParent } from "./util";
 
 const { ast } = template.expression;
@@ -103,11 +100,7 @@ export function transform(
     const replaceKey = isCall ? "callee" : "object";
 
     const chainWithTypes = node[replaceKey];
-    let chain = chainWithTypes;
-
-    while (isTransparentExprWrapper(chain)) {
-      chain = chain.expression;
-    }
+    const chain = skipTransparentExprWrappers(chainWithTypes);
 
     let ref;
     let check;
@@ -169,9 +162,7 @@ export function transform(
     // i.e. `?.b` in `(a?.b.c)()`
     if (i === 0 && parentIsCall) {
       // `(a?.b)()` to `(a == null ? undefined : a.b.bind(a))()`
-      const object = skipTransparentExprWrappers(
-        replacementPath.get("object"),
-      ).node;
+      const object = skipTransparentExprWrappers(replacement.object);
       let baseRef;
       if (!pureGetters || !isSimpleMemberExpression(object)) {
         // memoize the context object when getters are not always pure
diff --git a/packages/babel-plugin-proposal-optional-chaining/test/fixtures/transparent-expr-wrappers/ts-as-function-call-loose/output.js b/packages/babel-plugin-proposal-optional-chaining/test/fixtures/transparent-expr-wrappers/ts-as-function-call-loose/output.js
@@ -1,3 +1 @@
-var _bar, _ref;
-
-(_bar = ((_ref = (foo as A)).bar as B)) == null ? void 0 : _bar.call(_ref, foo.bar, false);
+((foo as A).bar as B) == null ? void 0 : ((foo as A).bar as B)(foo.bar, false);
diff --git a/tsconfig.json b/tsconfig.json
@@ -20,6 +20,7 @@
     "./packages/babel-helper-optimise-call-expression/src/**/*.ts",
     "./packages/babel-helper-replace-supers/src/**/*.ts",
     "./packages/babel-helper-simple-access/src/**/*.ts",
+    "./packages/babel-helper-skip-transparent-expression-wrappers/src/**/*.ts",
     "./packages/babel-helper-split-export-declaration/src/**/*.ts",
     "./packages/babel-helper-transform-fixture-test-runner/src/**/*.ts",
     "./packages/babel-helper-validator-identifier/src/**/*.ts",
@@ -94,6 +95,9 @@
       "@babel/helper-simple-access": [
         "./packages/babel-helper-simple-access/src"
       ],
+      "@babel/helper-skip-transparent-expression-wrappers": [
+        "./packages/babel-helper-skip-transparent-expression-wrappers/src"
+      ],
       "@babel/helper-split-export-declaration": [
         "./packages/babel-helper-split-export-declaration/src"
       ],
