feat(cactus-common): add Objects utility class to get owned and inher…

…ited methods of class instance

Signed-off-by: Peter Somogyvari <peter.somogyvari@accenture.com>

packages/cactus-common/src/main/typescript/objects.ts

@@ -0,0 +1,65 @@
+/**
+ * Utility class responsible for common and tedious tasks involving Javascript objects (instances of classes).
+ */
+export class Objects {
+  /**
+   * Returns a list of methods for an instance, including the inherited ones.
+   * Example:
+   *
+   * ```javascript
+   * class Base {
+   *   constructor() {
+   *   }
+   *   getX() {
+   *     return 'x';
+   *   }
+   * }
+   *
+   * class A extends Base {
+   *   getA() {
+   *     return 'a';
+   *   }
+   * }
+   *
+   * const a = new A();
+   * const methodNames = Objects.getAllMethodNames(a);
+   * console.log(methodNames);
+   * // [ 'getA', 'getX' ]
+   * ```
+   *
+   * @param anObject
+   */
+  public static getAllMethodNames(anObject: any): string[] {
+    let properties: string[] = [];
+    do {
+      const symbols = Object.getOwnPropertySymbols(anObject);
+      const symbolPropertyNames = symbols.map((aSymbol) => aSymbol.toString());
+
+      const propertyNamesCurrent = Object.getOwnPropertyNames(anObject)
+        .concat(symbolPropertyNames)
+        .sort()
+        .filter((propertyName: string, index: number, arr) => {
+          return (
+            typeof anObject[propertyName] === "function" &&
+            propertyName !== "constructor" &&
+            (index === 0 || propertyName !== arr[index - 1]) &&
+            properties.indexOf(propertyName) === -1
+          );
+        });
+
+      properties = properties.concat(propertyNamesCurrent);
+      anObject = Object.getPrototypeOf(anObject);
+    } while (anObject && Object.getPrototypeOf(anObject));
+    return properties;
+  }
+
+  public static getAllFieldNames(anObject: any): string[] {
+    const allFieldNames = [];
+    for (const propertyKey in anObject) {
+      if (anObject.hasOwnProperty(propertyKey)) {
+        allFieldNames.push(propertyKey);
+      }
+    }
+    return allFieldNames;
+  }
+}

packages/cactus-common/src/main/typescript/public-api.ts

@@ -1,3 +1,4 @@
 export { LoggerProvider } from "./logging/logger-provider";
 export { Logger, ILoggerOptions } from "./logging/logger";
 export { LogLevelDesc } from "loglevel";
+export { Objects } from "./objects";

packages/cactus-common/src/test/typescript/unit/objects/get-all-method-names.ts

@@ -0,0 +1,48 @@
+// tslint:disable: max-classes-per-file
+// tslint:disable-next-line: no-var-requires
+const tap = require("tap");
+import { Objects } from "../../../../main/typescript/public-api";
+
+class Base {
+  private readonly y: string;
+
+  constructor() {
+    this.y = "y";
+  }
+
+  getX() {
+    return "x";
+  }
+}
+
+class A extends Base {
+  private readonly b: string;
+
+  constructor() {
+    super();
+    this.b = "b";
+  }
+
+  getA() {
+    return "a";
+  }
+}
+
+tap.test("handles inheritance correctly", (assert: any) => {
+  const a = new A();
+  const methodNames = Objects.getAllMethodNames(a);
+  assert.ok(Array.isArray(methodNames), "expect an arran of strings returned");
+  assert.ok(
+    methodNames.length === 2,
+    "expect two items in said array of strings"
+  );
+  assert.ok(
+    methodNames.includes("getX"),
+    'expect "getX" in said array of strings'
+  );
+  assert.ok(
+    methodNames.includes("getA"),
+    'expect "getA" in said array of strings'
+  );
+  assert.end();
+});