Improve code quality and write tests

node_modules/@babel/helper-hoist-variables/lib/index.js

@@ -0,0 +1,63 @@
+"use strict";
+
+Object.defineProperty(exports, "__esModule", {
+  value: true
+});
+exports.default = _default;
+
+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; } }
+
+const visitor = {
+  Scope(path, state) {
+    if (state.kind === "let") path.skip();
+  },
+
+  Function(path) {
+    path.skip();
+  },
+
+  VariableDeclaration(path, state) {
+    if (state.kind && path.node.kind !== state.kind) return;
+    const nodes = [];
+    const declarations = path.get("declarations");
+    let firstId;
+
+    for (const declar of declarations) {
+      firstId = declar.node.id;
+
+      if (declar.node.init) {
+        nodes.push(t().expressionStatement(t().assignmentExpression("=", declar.node.id, declar.node.init)));
+      }
+
+      for (const name of Object.keys(declar.getBindingIdentifiers())) {
+        state.emit(t().identifier(name), name, declar.node.init !== null);
+      }
+    }
+
+    if (path.parentPath.isFor({
+      left: path.node
+    })) {
+      path.replaceWith(firstId);
+    } else {
+      path.replaceWithMultiple(nodes);
+    }
+  }
+
+};
+
+function _default(path, emit, kind = "var") {
+  path.traverse(visitor, {
+    kind,
+    emit
+  });
+}