Improve code quality and write tests

node_modules/@babel/helper-member-expression-to-functions/lib/index.js

@@ -0,0 +1,142 @@
+"use strict";
+
+Object.defineProperty(exports, "__esModule", {
+  value: true
+});
+exports.default = memberExpressionToFunctions;
+
+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; } }
+
+class AssignmentMemoiser {
+  constructor() {
+    this._map = new WeakMap();
+  }
+
+  has(key) {
+    return this._map.has(key);
+  }
+
+  get(key) {
+    if (!this.has(key)) return;
+
+    const record = this._map.get(key);
+
+    const {
+      value
+    } = record;
+    record.count--;
+
+    if (record.count === 0) {
+      return t().assignmentExpression("=", value, key);
+    }
+
+    return value;
+  }
+
+  set(key, value, count) {
+    return this._map.set(key, {
+      count,
+      value
+    });
+  }
+
+}
+
+const handle = {
+  memoise() {},
+
+  handle(member) {
+    const {
+      node,
+      parent,
+      parentPath
+    } = member;
+
+    if (parentPath.isUpdateExpression({
+      argument: node
+    })) {
+      const {
+        operator,
+        prefix
+      } = parent;
+      this.memoise(member, 2);
+      const value = t().binaryExpression(operator[0], t().unaryExpression("+", this.get(member)), t().numericLiteral(1));
+
+      if (prefix) {
+        parentPath.replaceWith(this.set(member, value));
+      } else {
+        const {
+          scope
+        } = member;
+        const ref = scope.generateUidIdentifierBasedOnNode(node);
+        scope.push({
+          id: ref
+        });
+        value.left = t().assignmentExpression("=", t().cloneNode(ref), value.left);
+        parentPath.replaceWith(t().sequenceExpression([this.set(member, value), t().cloneNode(ref)]));
+      }
+
+      return;
+    }
+
+    if (parentPath.isAssignmentExpression({
+      left: node
+    })) {
+      const {
+        operator,
+        right
+      } = parent;
+      let value = right;
+
+      if (operator !== "=") {
+        this.memoise(member, 2);
+        value = t().binaryExpression(operator.slice(0, -1), this.get(member), value);
+      }
+
+      parentPath.replaceWith(this.set(member, value));
+      return;
+    }
+
+    if (parentPath.isCallExpression({
+      callee: node
+    })) {
+      const {
+        arguments: args
+      } = parent;
+      parentPath.replaceWith(this.call(member, args));
+      return;
+    }
+
+    if (parentPath.isObjectProperty({
+      value: node
+    }) && parentPath.parentPath.isObjectPattern() || parentPath.isAssignmentPattern({
+      left: node
+    }) && parentPath.parentPath.isObjectProperty({
+      value: parent
+    }) && parentPath.parentPath.parentPath.isObjectPattern() || parentPath.isArrayPattern() || parentPath.isAssignmentPattern({
+      left: node
+    }) && parentPath.parentPath.isArrayPattern() || parentPath.isRestElement()) {
+      member.replaceWith(this.destructureSet(member));
+      return;
+    }
+
+    member.replaceWith(this.get(member));
+  }
+
+};
+
+function memberExpressionToFunctions(path, visitor, state) {
+  path.traverse(visitor, Object.assign({}, handle, state, {
+    memoiser: new AssignmentMemoiser()
+  }));
+}