Improve super.x output

packages/babel-helper-create-class-features-plugin/test/fixtures/replace-supers/method/output.js

@@ -9,5 +9,5 @@ class A extends B {
 _A = A;
 function _foo() {
  let _A2;
- babelHelpers.get(babelHelpers.getPrototypeOf(_A.prototype), "x", this);
+ babelHelpers.superPropertyGetCall(_A.prototype, "x", this);
 }

packages/babel-helper-replace-supers/src/index.ts

@@ -7,7 +7,6 @@ import { traverse, template, types as t } from "@babel/core";
 import type { NodePath, Scope } from "@babel/traverse";
 const {
  assignmentExpression,
- booleanLiteral,
  callExpression,
  cloneNode,
  identifier,
@@ -26,37 +25,6 @@ if (!process.env.BABEL_8_BREAKING && !USE_ESM && !IS_STANDALONE) {
  exports.skipAllButComputedKey = ns.skipAllButComputedKey;
 }
 
-type ThisRef = {
- needAccessFirst?: boolean;
- this: t.ThisExpression;
-};
-
-/**
- * Creates an expression which result is the proto of objectRef.
- *
- * @example <caption>isStatic === true</caption>
- *
- * helpers.getPrototypeOf(CLASS)
- *
- * @example <caption>isStatic === false</caption>
- *
- * helpers.getPrototypeOf(CLASS.prototype)
- */
-function getPrototypeOfExpression(
- objectRef: t.Identifier,
- isStatic: boolean,
- file: File,
- isPrivateMethod: boolean,
-) {
- objectRef = cloneNode(objectRef);
- const targetRef =
- isStatic || isPrivateMethod
- ? objectRef
- : memberExpression(objectRef, identifier("prototype"));
-
- return callExpression(file.addHelper("getPrototypeOf"), [targetRef]);
-}
-
 const visitor = traverse.visitors.merge<
  HandlerState<ReplaceState> & ReplaceState
 >([
@@ -116,12 +84,17 @@ interface SpecHandler
  | "optionalCall"
  | "delete"
  > {
- _get(
+ _get?(
  this: Handler & SpecHandler,
  superMember: SuperMember,
- thisRefs: ThisRef,
  ): t.CallExpression;
- _getThisRefs(): ThisRef;
+ _call?(
+ this: Handler & SpecHandler,
+ superMember: SuperMember,
+ args: t.CallExpression["arguments"],
+ optional: boolean,
+ ): t.CallExpression | t.OptionalCallExpression;
+ _getPrototypeOfExpression(this: Handler & SpecHandler): t.CallExpression;
  prop(this: Handler & SpecHandler, superMember: SuperMember): t.Expression;
 }
 
@@ -158,57 +131,222 @@ const specHandlers: SpecHandler = {
  return stringLiteral((property as t.Identifier).name);
  },
 
+ /**
+ * Creates an expression which result is the proto of objectRef.
+ *
+ * @example <caption>isStatic === true</caption>
+ *
+ * helpers.getPrototypeOf(CLASS)
+ *
+ * @example <caption>isStatic === false</caption>
+ *
+ * helpers.getPrototypeOf(CLASS.prototype)
+ */
+ _getPrototypeOfExpression(this: Handler & SpecHandler) {
+ const objectRef = cloneNode(this.getObjectRef());
+ const targetRef =
+ this.isStatic || this.isPrivateMethod
+ ? objectRef
+ : memberExpression(objectRef, identifier("prototype"));
+
+ return callExpression(this.file.addHelper("getPrototypeOf"), [targetRef]);
+ },
+
  get(this: Handler & SpecHandler, superMember: SuperMember) {
- return this._get(superMember, this._getThisRefs());
+ const objectRef = cloneNode(this.getObjectRef());
+ return callExpression(this.file.addHelper("superPropertyGetCall"), [
+ this.isDerivedConstructor
+ ? sequenceExpression([thisExpression(), objectRef])
+ : objectRef,
+ this.prop(superMember),
+ thisExpression(),
+ ...(this.isStatic || this.isPrivateMethod ? [] : [t.numericLiteral(1)]),
+ ]);
+ },
+
+ _call(
+ this: Handler & SpecHandler,
+ superMember: SuperMember,
+ args: t.CallExpression["arguments"],
+ optional: boolean,
+ ): t.CallExpression | t.OptionalCallExpression {
+ const objectRef = cloneNode(this.getObjectRef());
+ let argsNode: t.ArrayExpression | t.Identifier;
+ if (
+ args.length === 1 &&
+ t.isSpreadElement(args[0]) &&
+ (t.isIdentifier(args[0].argument) ||
+ t.isArrayExpression(args[0].argument))
+ ) {
+ argsNode = args[0].argument;
+ } else {
+ argsNode = t.arrayExpression(args as t.Expression[]);
+ }
+ const buildArgs = [
+ this.file.addHelper("superPropertyGetCall"),
+ [
+ this.isDerivedConstructor
+ ? sequenceExpression([thisExpression(), objectRef])
+ : objectRef,
+ this.prop(superMember),
+ thisExpression(),
+ t.numericLiteral(this.isStatic || this.isPrivateMethod ? 0 : 1),
+ argsNode,
+ ],
+ ] as Parameters<typeof t.callExpression>;
+ if (optional) {
+ return t.optionalCallExpression(
+ buildArgs[0] as t.Expression,
+ buildArgs[1],
+ true,
+ );
+ }
+ return callExpression(...buildArgs);
  },
 
- _get(
+ set(
  this: Handler & SpecHandler,
  superMember: SuperMember,
- thisRefs: ThisRef,
+ value: t.Expression,
  ) {
- const proto = getPrototypeOfExpression(
- this.getObjectRef(),
- this.isStatic,
- this.file,
- this.isPrivateMethod,
+ const objectRef = cloneNode(this.getObjectRef());
+
+ return callExpression(this.file.addHelper("superPropertySet"), [
+ this.isDerivedConstructor
+ ? sequenceExpression([thisExpression(), objectRef])
+ : objectRef,
+ this.prop(superMember),
+ value,
+ thisExpression(),
+ t.numericLiteral(superMember.isInStrictMode() ? 1 : 0),
+ ...(this.isStatic || this.isPrivateMethod ? [] : [t.numericLiteral(1)]),
+ ]);
+ },
+
+ destructureSet(this: Handler & SpecHandler, superMember: SuperMember) {
+ throw superMember.buildCodeFrameError(
+ `Destructuring to a super field is not supported yet.`,
  );
+ },
+
+ call(
+ this: Handler & SpecHandler,
+ superMember: SuperMember,
+ args: t.CallExpression["arguments"],
+ ) {
+ return this._call(superMember, args, false);
+ },
+
+ optionalCall(
+ this: Handler & SpecHandler,
+ superMember: SuperMember,
+ args: t.CallExpression["arguments"],
+ ) {
+ return this._call(superMember, args, true);
+ },
+
+ delete(this: Handler & SpecHandler, superMember: SuperMember) {
+ if (superMember.node.computed) {
+ return sequenceExpression([
+ callExpression(this.file.addHelper("toPropertyKey"), [
+ cloneNode(superMember.node.property),
+ ]),
+ template.expression.ast`
+ function () { throw new ReferenceError("'delete super[expr]' is invalid"); }()
+ `,
+ ]);
+ } else {
+ return template.expression.ast`
+ function () { throw new ReferenceError("'delete super.prop' is invalid"); }()
+ `;
+ }
+ },
+};
+
+const specHandlers_old: SpecHandler = {
+ memoise(
+ this: Handler & SpecHandler,
+ superMember: SuperMember,
+ count: number,
+ ) {
+ const { scope, node } = superMember;
+ const { computed, property } = node;
+ if (!computed) {
+ return;
+ }
+
+ const memo = scope.maybeGenerateMemoised(property);
+ if (!memo) {
+ return;
+ }
+
+ this.memoiser.set(property, memo, count);
+ },
+
+ prop(this: Handler & SpecHandler, superMember: SuperMember) {
+ const { computed, property } = superMember.node;
+ if (this.memoiser.has(property)) {
+ return cloneNode(this.memoiser.get(property));
+ }
+
+ if (computed) {
+ return cloneNode(property);
+ }
+
+ return stringLiteral((property as t.Identifier).name);
+ },
+
+ /**
+ * Creates an expression which result is the proto of objectRef.
+ *
+ * @example <caption>isStatic === true</caption>
+ *
+ * helpers.getPrototypeOf(CLASS)
+ *
+ * @example <caption>isStatic === false</caption>
+ *
+ * helpers.getPrototypeOf(CLASS.prototype)
+ */
+ _getPrototypeOfExpression(this: Handler & SpecHandler) {
+ const objectRef = cloneNode(this.getObjectRef());
+ const targetRef =
+ this.isStatic || this.isPrivateMethod
+ ? objectRef
+ : memberExpression(objectRef, identifier("prototype"));
+
+ return callExpression(this.file.addHelper("getPrototypeOf"), [targetRef]);
+ },
+
+ get(this: Handler & SpecHandler, superMember: SuperMember) {
+ return this._get(superMember);
+ },
+
+ _get(this: Handler & SpecHandler, superMember: SuperMember) {
+ const proto = this._getPrototypeOfExpression();
  return callExpression(this.file.addHelper("get"), [
- thisRefs.needAccessFirst
- ? sequenceExpression([thisRefs.this, proto])
+ this.isDerivedConstructor
+ ? sequenceExpression([thisExpression(), proto])
  : proto,
  this.prop(superMember),
- thisRefs.this,
+ thisExpression(),
  ]);
  },
 
- _getThisRefs(this: Handler & SpecHandler): ThisRef {
- return {
- needAccessFirst: this.isDerivedConstructor,
- this: thisExpression(),
- };
- },
-
  set(
  this: Handler & SpecHandler,
  superMember: SuperMember,
  value: t.Expression,
  ) {
- const thisRefs = this._getThisRefs();
- const proto = getPrototypeOfExpression(
- this.getObjectRef(),
- this.isStatic,
- this.file,
- this.isPrivateMethod,
- );
+ const proto = this._getPrototypeOfExpression();
+
  return callExpression(this.file.addHelper("set"), [
- thisRefs.needAccessFirst
- ? sequenceExpression([thisRefs.this, proto])
+ this.isDerivedConstructor
+ ? sequenceExpression([thisExpression(), proto])
  : proto,
  this.prop(superMember),
  value,
- thisRefs.this,
- booleanLiteral(superMember.isInStrictMode()),
+ thisExpression(),
+ t.booleanLiteral(superMember.isInStrictMode()),
  ]);
  },
 
@@ -223,24 +361,17 @@ const specHandlers: SpecHandler = {
  superMember: SuperMember,
  args: t.CallExpression["arguments"],
  ) {
- const thisRefs = this._getThisRefs();
- return optimiseCall(
- this._get(superMember, thisRefs),
- cloneNode(thisRefs.this),
- args,
- false,
- );
+ return optimiseCall(this._get(superMember), thisExpression(), args, false);
  },
 
  optionalCall(
  this: Handler & SpecHandler,
  superMember: SuperMember,
  args: t.CallExpression["arguments"],
  ) {
- const thisRefs = this._getThisRefs();
  return optimiseCall(
- this._get(superMember, thisRefs),
- cloneNode(thisRefs.this),
+ this._get(superMember),
+ cloneNode(thisExpression()),
  args,
  true,
  );
@@ -424,7 +555,12 @@ export default class ReplaceSupers {
  });
  }
 
- const handler = this.constantSuper ? looseHandlers : specHandlers;
+ const handler = this.constantSuper
+ ? looseHandlers
+ : process.env.BABEL_8_BREAKING ||
+ this.file.availableHelper("superPropertySet")
+ ? specHandlers
+ : specHandlers_old;
 
  // todo: this should have been handled by the environmentVisitor,
  // consider add visitSelf support for the path.traverse

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

@@ -163,6 +163,16 @@ export default Object.freeze({
  "7.23.6",
  'export default function setFunctionName(e,t,n){"symbol"==typeof t&&(t=(t=t.description)?"["+t+"]":"");try{Object.defineProperty(e,"name",{configurable:!0,value:n?n+" "+t:t})}catch(e){}return e}',
  ),
+ // size: 192, gzip size: 151
+ superPropertyGetCall: helper(
+ "7.24.4",
+ 'import get from"get";import getPrototypeOf from"getPrototypeOf";export default function _superPropertyGetCall(t,e,o,r,p){var f=get(getPrototypeOf(r?t.prototype:t),e,o);return p?f.apply(o,p):f}',
+ ),
+ // size: 171, gzip size: 133
+ superPropertySet: helper(
+ "7.24.4",
+ 'import set from"set";import getPrototypeOf from"getPrototypeOf";export default function _superPropertySet(t,e,o,r,p,f){return set(getPrototypeOf(f?t.prototype:t),e,o,r,p)}',
+ ),
  // size: 285, gzip size: 210
  toPrimitive: helper(
  "7.1.5",