Initial commit.

.gitattributes

+# Disable line-ending conversions for this repository.
+* -text

.gitignore

+# dependencies
+/node_modules
+
+# testing
+/coverage
+
+# production
+/build
+
+# environments
+.env.local
+.env.development.local
+.env.test.local
+.env.production.local
+
+# logs
+npm-debug.log*
+yarn-debug.log*
+yarn-error.log*
+
+# misc
+*~
+.DS_Store

.gitmodules

+[submodule "eslint-config"]
+	path = eslint-config
+	url = git@git.unl.edu:csce-310/eslint-config.git

README.md

+# Tests-Only Starter Code
+
+A minimal project to be used as starter code for Homework 5 in the 250 section
+of the CSCE 310 course at UNL.
+
+# Quick Start
+
+Recursively clone this repository and `cd` into the root folder:
+
+```
+$ git clone --recursive git@git.unl.edu:csce-310/2021-fall-homework-5.git
+$ cd 2021-fall-homework-5
+```
+
+(If you forget `--recursive` when cloning, you can `cd` into your clone and run
+`git submodule update --init --recursive` instead.)
+
+Install dependencies:
+
+```
+$ npm install
+```
+
+# Instructions
+
+See <https://canvas.unl.edu/courses/114253/assignments/1116786>.

eslint-config @ 24df42fb

+Subproject commit 24df42fb655d234b83c93b0fb24d012e4d9ecb58

homework-5.code-workspace

+{
+	"folders": [
+		{
+			"path": "."
+		}
+	],
+	"settings": {
+		"files.eol": "LF",
+		"files.exclude": {
+			"**/node_modules": true
+		},
+		"files.trimFinalNewlines": true,
+		"files.trimTrailingWhitespace": true
+	}
+}

homework-5/.gitignore

+# dependencies
+/node_modules
+
+# testing
+/coverage
+
+# production
+/build
+
+# environments
+.env.local
+.env.development.local
+.env.test.local
+.env.production.local
+
+# logs
+npm-debug.log*
+yarn-debug.log*
+yarn-error.log*
+
+# misc
+*~
+.DS_Store

homework-5/package.json

+{
+  "name": "@unlsoft/homework-5-implementation",
+  "version": "1.0.0",
+  "description": "A minimal project to be used as starter code for Homework 5.",
+  "type": "module",
+  "private": true,
+  "license": "UNLICENSED",
+  "scripts": {
+    "lint:js": "eslint --max-warnings 0 ./src",
+    "lint": "run-s --continue-on-error lint:**",
+    "test-once:add": "node --experimental-vm-modules node_modules/jest/bin/jest.js --coverage -t \"correctly inserts values\"",
+    "test-once:addAndDelete": "node --experimental-vm-modules node_modules/jest/bin/jest.js --coverage -t \"correctly inserts and removes values\"",
+    "test-once": "node --experimental-vm-modules node_modules/jest/bin/jest.js --coverage",
+    "test": "node --experimental-vm-modules node_modules/jest/bin/jest.js --watchAll --coverage"
+  },
+  "dependencies": {
+    "npm-run-all": "^4.1.5"
+  },
+  "devDependencies": {
+    "@unlsoft/eslint-config": "file:../eslint-config",
+    "eslint": "^7.30.0",
+    "jest": "^27.0.6",
+    "jest-environment-node": "^27.0.6"
+  },
+  "eslintConfig": {
+    "extends": "@unlsoft"
+  },
+  "jest": {
+    "clearMocks": true,
+    "collectCoverageFrom": [
+      "src/**/*.js",
+      "!src/testing/**/*.js"
+    ],
+    "resetMocks": false,
+    "restoreMocks": false,
+    "testEnvironment": "./src/testing/failFast.js",
+    "transform": {}
+  },
+  "//": [
+    "See https://github.com/facebook/jest/issues/9430 for information on Jest+ES6."
+  ]
+}

homework-5/src/testing/failFast.js

+import NodeEnvironment from 'jest-environment-node';
+
+export default class FailFastEnvironment extends NodeEnvironment {
+  constructor(...rest) {
+    super(...rest);
+    this.failed = false;
+  }
+
+  async handleTestEvent(event, state) {
+    switch (event.name) {
+    case 'hook_failure':
+    case 'test_fn_failure':
+      this.failed = true;
+      break;
+    case 'test_start':
+      if (this.failed) {
+        event.test.mode = 'skip';
+      }
+      break;
+    default:
+    }
+    if (super.handleTestEvent !== undefined) {
+      await super.handleTestEvent(event, state);
+    }
+  }
+
+  async teardown() {
+    // Preserve the VM context so that we can use `import` in async tests (the
+    // fact that we have to do this is almost certainly a bug in Jest).
+    const preservedContext = this.context;
+    await super.teardown();
+    this.context = preservedContext;
+  }
+}

homework-5/src/tree.js

+// INSTRUCTIONS: An unbalanced ternary leafy tree is a tree data structure where:
+//
+// * all elements are stored in leaves,
+//
+// * every branch has at most three children, and every branch also tracks the
+//   greatest element from among its descendants, and
+//
+// * no code is included to keep the tree balanced.
+//
+// It has five invariants that must be maintained in order to be valid:
+//
+// 1. Every branch must have either two or three children (`aritiesOkay`),
+//
+// 2. The root vertex, if it exists, must not have a parent (`rootOkay`),
+//
+// 3. The child of any vertex must know that that vertex is its parent
+//    (`linksOkay`),
+//
+// 4. The memoized greatest element in a branch must be the greatest element
+//    from that branch's descendants (`greatestsOkay`), and
+//
+// 5. The tree's elements must be sorted from left to right
+// (`childrenOrderOkay`).
+//
+// Starter code for an unbalanced ternary leafy tree is provided below.
+// Complete that JavaScript, in particular the `add` and `delete` methods, so
+// that the data structure can insert and remove elements while maintaining the
+// invariants listed above.  (You may also find it helpful to break some of your
+// logic out into helper methods.)
+//
+// Unit tests are provided to check functional correctness by comparing string
+// representations of the tree to expected strings as elements are added and
+// removed.  The tests also contain extra statements like
+// `expect(tree.aritiesOkay).toBe(true);` to warn you as soon as any of the five
+// invariants listed above are violated—they can help you spot problems early,
+// without having to wait for them to affect later insertions or deletions.
+
+// INSTRUCTIONS: While normally it is a bad idea to turn off linter warnings, in
+// code for linked data structures you may safely disable the following checks
+// if they are triggering false positives:
+
+// /* eslint-disable consistent-this */
+// /* eslint-disable no-use-before-define */
+
+const ARITY = 3;
+
+function byGreatest(left, right) {
+  return left.greatest - right.greatest;
+}
+
+// eslint-disable-next-line no-unused-vars -- INSTRUCTIONS: Remove this comment once you use the Leaf class.
+class Leaf {
+  constructor(element) {
+    this.parent = undefined;
+    this.element = element;
+  }
+
+  get greatest() {
+    return this.element;
+  }
+
+  get aritiesOkay() {
+    return true;
+  }
+
+  get linksOkay() {
+    return true;
+  }
+
+  get greatestsOkay() {
+    return true;
+  }
+
+  get childrenOrderOkay() {
+    return true;
+  }
+
+  toString() {
+    return `${this.element}`;
+  }
+}
+
+// eslint-disable-next-line no-unused-vars -- INSTRUCTIONS: Remove this comment once you use the Branch class.
+class Branch {
+  constructor(parent, children) {
+    this.parent = parent;
+    this.children = children.sort(byGreatest);
+    this.greatest = this.lastChild.greatest;
+  }
+
+  get full() {
+    return this.children.length >= ARITY;
+  }
+
+  get lastChild() {
+    return this.children[this.children.length - 1];
+  }
+
+  get aritiesOkay() {
+    return this.children.length > 1 && this.children.length <= ARITY &&
+      this.children.every((child) => child.aritiesOkay);
+  }
+
+  get linksOkay() {
+    return this.children.every((child) => child.parent === this && child.linksOkay);
+  }
+
+  get greatestsOkay() {
+    return this.greatest === this.lastChild.greatest && this.children.every((child) => child.greatestsOkay);
+  }
+
+  get childrenOrderOkay() {
+    for (let i = 0; i < this.children.length - 1; ++i) {
+      if (this.children[i].greatest > this.children[i + 1].greatest) {
+        return false;
+      }
+    }
+    return this.children.every((child) => child.childrenOrderOkay);
+  }
+
+  toString() {
+    const contents = this.children.map((child) => `${child}`);
+    return `max(${contents.join(', ')}) = ${this.greatest}`;
+  }
+}
+
+export class LeafyTree {
+  constructor() {
+    this.root = undefined;
+  }
+
+  add(element) {
+    // INSTRUCTIONS: Complete this JavaScript method (and any other helper
+    // methods you deem necessary) so that it will add an element to the tree.
+    // The current code is just a placeholder and should be replaced.
+  }
+
+  delete(element) {
+    // INSTRUCTIONS: Complete this JavaScript method (and any other helper
+    // methods you deem necessary) so that it will remove an element from the
+    // tree.
+  }
+
+  get aritiesOkay() {
+    return this.root === undefined || this.root.aritiesOkay;
+  }
+
+  get rootOkay() {
+    return this.root === undefined || this.root.parent === undefined;
+  }
+
+  get linksOkay() {
+    return this.root === undefined || this.root.linksOkay;
+  }
+
+  get greatestsOkay() {
+    return this.root === undefined || this.root.greatestsOkay;
+  }
+
+  get childrenOrderOkay() {
+    return this.root === undefined || this.root.childrenOrderOkay;
+  }
+
+  toString() {
+    return this.root !== undefined ? `${this.root}` : '∅';
+  }
+}

package.json

+{
+  "name": "@unlsoft/homework-5",
+  "version": "1.0.0",
+  "description": "A project skeleton to be used as starter code for Homework 5.",
+  "private": true,
+  "license": "UNLICENSED",
+  "scripts": {
+    "postinstall:eslint-config": "cd eslint-config && npm install",
+    "postinstall:app": "cd homework-5 && npm install",
+    "postinstall": "run-s postinstall:**",
+    "lint:app": "cd homework-5 && npm run lint",
+    "lint": "run-s --continue-on-error lint:**",
+    "test-once:add": "cd homework-5 && npm run test-once:add",
+    "test-once:addAndDelete": "cd homework-5 && npm run test-once:addAndDelete",
+    "test-once": "cd homework-5 && npm run test-once",
+    "test": "run-s test-once",
+    "start": "cd homework-5 && npm run start",
+    "build:app": "cd homework-5 && npm run build",
+    "build": "run-s build:**"
+  },
+  "devDependencies": {
+    "ghooks": "^2.0.4",
+    "npm-run-all": "^4.1.5"
+  },
+  "config": {
+    "ghooks": {
+      "pre-commit": "npm run lint"
+    }
+  }
+}