Improve code quality and write tests

node_modules/@babel/helper-call-delegate/lib/index.js

@@ -0,0 +1,84 @@
+"use strict";
+
+Object.defineProperty(exports, "__esModule", {
+  value: true
+});
+exports.default = _default;
+
+function _helperHoistVariables() {
+  const data = _interopRequireDefault(require("@babel/helper-hoist-variables"));
+
+  _helperHoistVariables = function () {
+    return data;
+  };
+
+  return data;
+}
+
+function t() {
+  const data = _interopRequireWildcard(require("@babel/types"));
+
+  t = function () {
+    return data;
+  };
+
+  return data;
+}
+
+function _interopRequireWildcard(obj) { if (obj && obj.__esModule) { return obj; } else { var newObj = {}; if (obj != null) { for (var key in obj) { if (Object.prototype.hasOwnProperty.call(obj, key)) { var desc = Object.defineProperty && Object.getOwnPropertyDescriptor ? Object.getOwnPropertyDescriptor(obj, key) : {}; if (desc.get || desc.set) { Object.defineProperty(newObj, key, desc); } else { newObj[key] = obj[key]; } } } } newObj.default = obj; return newObj; } }
+
+function _interopRequireDefault(obj) { return obj && obj.__esModule ? obj : { default: obj }; }
+
+const visitor = {
+  enter(path, state) {
+    if (path.isThisExpression()) {
+      state.foundThis = true;
+    }
+
+    if (path.isReferencedIdentifier({
+      name: "arguments"
+    })) {
+      state.foundArguments = true;
+    }
+  },
+
+  Function(path) {
+    path.skip();
+  }
+
+};
+
+function _default(path, scope = path.scope) {
+  const {
+    node
+  } = path;
+  const container = t().functionExpression(null, [], node.body, node.generator, node.async);
+  let callee = container;
+  let args = [];
+  (0, _helperHoistVariables().default)(path, id => scope.push({
+    id
+  }));
+  const state = {
+    foundThis: false,
+    foundArguments: false
+  };
+  path.traverse(visitor, state);
+
+  if (state.foundArguments || state.foundThis) {
+    callee = t().memberExpression(container, t().identifier("apply"));
+    args = [];
+
+    if (state.foundThis) {
+      args.push(t().thisExpression());
+    }
+
+    if (state.foundArguments) {
+      if (!state.foundThis) args.push(t().nullLiteral());
+      args.push(t().identifier("arguments"));
+    }
+  }
+
+  let call = t().callExpression(callee, args);
+  if (node.generator) call = t().yieldExpression(call, true);
+  return t().returnStatement(call);
+}