Simplify (transpiled) babel-types builder wrappers (#13843)

packages/babel-types/scripts/generators/builders.js

@@ -100,7 +100,7 @@ import type * as t from "../..";
       formatedBuilderNameLocal === formatedBuilderName ? "export " : ""
     }function ${formatedBuilderNameLocal}(${defArgs.join(
       ", "
-    )}): t.${type} { return builder("${type}", ...arguments); }\n`;
+    )}): t.${type} { return builder.apply("${type}", arguments); }\n`;
     if (formatedBuilderNameLocal !== formatedBuilderName) {
       output += `export { ${formatedBuilderNameLocal} as ${formatedBuilderName} };\n`;
     }
@@ -119,9 +119,9 @@ import type * as t from "../..";
     const newType = definitions.DEPRECATED_KEYS[type];
     const formatedBuilderName = formatBuilderName(type);
     output += `/** @deprecated */
-function ${type}(...args: Array<any>): any {
+function ${type}(${generateBuilderArgs(newType).join(", ")}): t.${type} {
   console.trace("The node type ${type} has been renamed to ${newType}");
-  return builder("${type}", ...args);
+  return builder.apply("${type}", arguments);
 }
 export { ${type} as ${formatedBuilderName} };\n`;
     // This is needed for backwards compatibility.

packages/babel-types/src/builders/builder.ts

@@ -2,12 +2,10 @@ import { NODE_FIELDS, BUILDER_KEYS } from "../definitions";
 import validate from "../validators/validate";
 import type * as t from "..";
 
-export default function builder<T extends t.Node>(
+export default function builder<T extends t.Node>(this: T["type"]): T {
-  type: T["type"],
+  const type = this;
-  ...args: Array<any>
-): T {
   const keys = BUILDER_KEYS[type];
-  const countArgs = args.length;
+  const countArgs = arguments.length;
   if (countArgs > keys.length) {
     throw new Error(
       `${type}: Too many arguments passed. Received ${countArgs} but can receive no more than ${keys.length}`,
@@ -16,21 +14,22 @@ export default function builder<T extends t.Node>(
 
   const node = { type };
 
-  let i = 0;
+  for (let i = 0; i < keys.length; ++i) {
-  keys.forEach(key => {
+    const key = keys[i];
     const field = NODE_FIELDS[type][key];
 
     let arg;
-    if (i < countArgs) arg = args[i];
+    if (i < countArgs) arg = arguments[i];
     if (arg === undefined) {
       arg = Array.isArray(field.default) ? [] : field.default;
     }
 
     node[key] = arg;
-    i++;
+  }
-  });
 
-  for (const key of Object.keys(node)) {
+  // (assume all enumerable properties are own)
+  // eslint-disable-next-line guard-for-in
+  for (const key in node) {
     validate(node as t.Node, key, node[key]);
   }
 

packages/babel-types/src/definitions/index.ts

@@ -31,9 +31,11 @@ toFastProperties(DEPRECATED_KEYS);
 toFastProperties(PLACEHOLDERS_ALIAS);
 toFastProperties(PLACEHOLDERS_FLIPPED_ALIAS);
 
-const TYPES: Array<string> = Object.keys(VISITOR_KEYS)
+const TYPES: Array<string> = [].concat(
-  .concat(Object.keys(FLIPPED_ALIAS_KEYS))
+  Object.keys(VISITOR_KEYS),
-  .concat(Object.keys(DEPRECATED_KEYS));
+  Object.keys(FLIPPED_ALIAS_KEYS),
+  Object.keys(DEPRECATED_KEYS),
+);
 
 export {
   VISITOR_KEYS,