[feature] - Add latches

Author: robwilson1

.eslintrc.js

@@ -1,47 +1,30 @@
 module.exports = {
-	"env": {
-		"browser": true,
-		"es6": true
+	env: {
+		browser: true,
+		es6: true,
+		jest: true,
 	},
-	"extends": [
-		"eslint:recommended",
-		"prettier",
-	],
-	"globals": {
-		"Atomics": "readonly",
-		"SharedArrayBuffer": "readonly"
+	extends: ["eslint:recommended", "prettier"],
+	globals: {
+		Atomics: "readonly",
+		SharedArrayBuffer: "readonly",
 	},
-	"parserOptions": {
-		"ecmaVersion": 2019,
-		"sourceType": "module"
+	parserOptions: {
+		ecmaVersion: 2019,
+		sourceType: "module",
 	},
-	"plugins": [
-		"svelte3",
-		"prettier"
-	],
+	plugins: ["svelte3", "prettier"],
 	overrides: [
 		{
-		  files: ['**/*.svelte'],
-		  processor: 'svelte3/svelte3'
-		}
+			files: ["**/*.svelte"],
+			processor: "svelte3/svelte3",
+		},
 	],
-	"rules": {
+	rules: {
 		"prettier/prettier": "error",
-		"indent": [
-			"error",
-			"tab"
-		],
-		"linebreak-style": [
-			"error",
-			"unix"
-		],
-		"quotes": [
-			"error",
-			"double"
-		],
-		"semi": [
-			"error",
-			"always"
-		]
-	}
+		indent: ["error", "tab"],
+		"linebreak-style": ["error", "unix"],
+		quotes: ["error", "double"],
+		semi: ["error", "always"],
+	},
 };

babel.config.js

@@ -0,0 +1,12 @@
+module.exports = {
+	presets: [
+		[
+			"@babel/preset-env",
+			{
+				targets: {
+					node: "current",
+				},
+			},
+		],
+	],
+};

jest.config.js

@@ -0,0 +1,188 @@
+// For a detailed explanation regarding each configuration property, visit:
+// https://jestjs.io/docs/en/configuration.html
+
+module.exports = {
+	// All imported modules in your tests should be mocked automatically
+	// automock: false,
+
+	// Stop running tests after `n` failures
+	// bail: 0,
+
+	// Respect "browser" field in package.json when resolving modules
+	// browser: false,
+
+	// The directory where Jest should store its cached dependency information
+	// cacheDirectory: "C:\\Users\\Rob\\AppData\\Local\\Temp\\jest",
+
+	// Automatically clear mock calls and instances between every test
+	clearMocks: true,
+
+	// Indicates whether the coverage information should be collected while executing the test
+	// collectCoverage: false,
+
+	// An array of glob patterns indicating a set of files for which coverage information should be collected
+	// collectCoverageFrom: undefined,
+
+	// The directory where Jest should output its coverage files
+	coverageDirectory: "coverage",
+
+	// An array of regexp pattern strings used to skip coverage collection
+	// coveragePathIgnorePatterns: [
+	//   "\\\\node_modules\\\\"
+	// ],
+
+	// A list of reporter names that Jest uses when writing coverage reports
+	// coverageReporters: [
+	//   "json",
+	//   "text",
+	//   "lcov",
+	//   "clover"
+	// ],
+
+	// An object that configures minimum threshold enforcement for coverage results
+	// coverageThreshold: undefined,
+
+	// A path to a custom dependency extractor
+	// dependencyExtractor: undefined,
+
+	// Make calling deprecated APIs throw helpful error messages
+	// errorOnDeprecated: false,
+
+	// Force coverage collection from ignored files using an array of glob patterns
+	// forceCoverageMatch: [],
+
+	// A path to a module which exports an async function that is triggered once before all test suites
+	// globalSetup: undefined,
+
+	// A path to a module which exports an async function that is triggered once after all test suites
+	// globalTeardown: undefined,
+
+	// A set of global variables that need to be available in all test environments
+	// globals: {},
+
+	// The maximum amount of workers used to run your tests. Can be specified as % or a number. E.g. maxWorkers: 10% will use 10% of your CPU amount + 1 as the maximum worker number. maxWorkers: 2 will use a maximum of 2 workers.
+	// maxWorkers: "50%",
+
+	// An array of directory names to be searched recursively up from the requiring module's location
+	// moduleDirectories: [
+	//   "node_modules"
+	// ],
+
+	// An array of file extensions your modules use
+	// moduleFileExtensions: [
+	//   "js",
+	//   "json",
+	//   "jsx",
+	//   "ts",
+	//   "tsx",
+	//   "node"
+	// ],
+
+	// A map from regular expressions to module names or to arrays of module names that allow to stub out resources with a single module
+	// moduleNameMapper: {},
+
+	// An array of regexp pattern strings, matched against all module paths before considered 'visible' to the module loader
+	// modulePathIgnorePatterns: [],
+
+	// Activates notifications for test results
+	// notify: false,
+
+	// An enum that specifies notification mode. Requires { notify: true }
+	// notifyMode: "failure-change",
+
+	// A preset that is used as a base for Jest's configuration
+	// preset: undefined,
+
+	// Run tests from one or more projects
+	// projects: undefined,
+
+	// Use this configuration option to add custom reporters to Jest
+	// reporters: undefined,
+
+	// Automatically reset mock state between every test
+	// resetMocks: false,
+
+	// Reset the module registry before running each individual test
+	// resetModules: false,
+
+	// A path to a custom resolver
+	// resolver: undefined,
+
+	// Automatically restore mock state between every test
+	// restoreMocks: false,
+
+	// The root directory that Jest should scan for tests and modules within
+	// rootDir: undefined,
+
+	// A list of paths to directories that Jest should use to search for files in
+	// roots: [
+	//   "<rootDir>"
+	// ],
+
+	// Allows you to use a custom runner instead of Jest's default test runner
+	// runner: "jest-runner",
+
+	// The paths to modules that run some code to configure or set up the testing environment before each test
+	// setupFiles: [],
+
+	// A list of paths to modules that run some code to configure or set up the testing framework before each test
+	// setupFilesAfterEnv: [],
+
+	// A list of paths to snapshot serializer modules Jest should use for snapshot testing
+	// snapshotSerializers: [],
+
+	// The test environment that will be used for testing
+	testEnvironment: "node",
+
+	// Options that will be passed to the testEnvironment
+	// testEnvironmentOptions: {},
+
+	// Adds a location field to test results
+	// testLocationInResults: false,
+
+	// The glob patterns Jest uses to detect test files
+	// testMatch: [
+	//   "**/__tests__/**/*.[jt]s?(x)",
+	//   "**/?(*.)+(spec|test).[tj]s?(x)"
+	// ],
+
+	// An array of regexp pattern strings that are matched against all test paths, matched tests are skipped
+	// testPathIgnorePatterns: [
+	//   "\\\\node_modules\\\\"
+	// ],
+
+	// The regexp pattern or array of patterns that Jest uses to detect test files
+	// testRegex: [],
+
+	// This option allows the use of a custom results processor
+	// testResultsProcessor: undefined,
+
+	// This option allows use of a custom test runner
+	// testRunner: "jasmine2",
+
+	// This option sets the URL for the jsdom environment. It is reflected in properties such as location.href
+	// testURL: "http://localhost",
+
+	// Setting this value to "fake" allows the use of fake timers for functions such as "setTimeout"
+	// timers: "real",
+
+	// A map from regular expressions to paths to transformers
+	// transform: undefined,
+
+	// An array of regexp pattern strings that are matched against all source file paths, matched files will skip transformation
+	// transformIgnorePatterns: [
+	//   "\\\\node_modules\\\\"
+	// ],
+
+	// An array of regexp pattern strings that are matched against all modules before the module loader will automatically return a mock for them
+	// unmockedModulePathPatterns: undefined,
+
+	// Indicates whether each individual test should be reported during the run
+	// verbose: undefined,
+
+	// An array of regexp patterns that are matched against all source file paths before re-running tests in watch mode
+	// watchPathIgnorePatterns: [],
+
+	// Whether to use watchman for file crawling
+	// watchman: true,
+};

package.json

@@ -7,15 +7,20 @@
 	"scripts": {
 		"build": "rollup -c",
 		"dev": "rollup -c -w",
-		"start": "sirv public"
+		"start": "sirv public",
+		"test:unit": "jest"
 	},
 	"devDependencies": {
+		"@babel/core": "^7.9.0",
+		"@babel/preset-env": "^7.9.5",
 		"@rollup/plugin-commonjs": "11.0.2",
 		"@rollup/plugin-node-resolve": "^7.0.0",
+		"babel-jest": "^25.3.0",
 		"eslint": "^6.8.0",
 		"eslint-config-prettier": "^6.10.1",
 		"eslint-plugin-prettier": "^3.1.3",
 		"eslint-plugin-svelte3": "^2.7.3",
+		"jest": "^25.3.0",
 		"prettier": "^2.0.4",
 		"rollup": "^1.20.0",
 		"rollup-plugin-livereload": "^1.0.0",

src/components/gates/not.js

@@ -3,6 +3,6 @@
  * @param {0b0 | 0b1} input - A single bit
  * @returns {0b0 | 0b1}
  */
-export function not(input = 0b0) {
+export function notGate(input = 0b0) {
 	return input ? 0b0 : 0b1;
 }

src/components/latches/and-or.js

@@ -0,0 +1,19 @@
+import { orGate, andGate, notGate } from "../gates";
+
+const defaultBit = 0b0;
+
+export class AndOrLatch {
+	constructor() {
+		this.current = defaultBit;
+	}
+
+	get output() {
+		return this.current;
+	}
+
+	trigger(set = defaultBit, reset = defaultBit) {
+		const orResult = orGate(this.current, set);
+		const andResult = andGate(orResult, notGate(reset));
+		this.current = andResult;
+	}
+}

src/components/latches/gated.js

@@ -0,0 +1,20 @@
+import { andGate, notGate } from "../gates";
+import { AndOrLatch } from "./and-or";
+
+const defaultBit = 0b0;
+
+export class GatedLatch {
+	constructor() {
+		this.andOrLatch = new AndOrLatch();
+	}
+
+	get output() {
+		return this.andOrLatch.current;
+	}
+
+	trigger(dataInput = defaultBit, writeEnable = defaultBit) {
+		const set = andGate(dataInput, writeEnable);
+		const reset = andGate(notGate(dataInput), writeEnable);
+		this.andOrLatch.trigger(set, reset);
+	}
+}

src/components/latches/tests/and-or.test.js

@@ -0,0 +1,48 @@
+import { AndOrLatch } from "../and-or";
+
+describe("Latches - AndOrLatch", () => {
+	test("new latch outputs 0", () => {
+		const latch = new AndOrLatch();
+		expect(latch.output).toBe(0b0);
+	});
+
+	test("Setting input to 1 outputs 1", () => {
+		const latch = new AndOrLatch();
+		latch.trigger(0b1, 0b0);
+		expect(latch.output).toBe(0b1);
+	});
+
+	test("Setting input to 0 outputs 0", () => {
+		const latch = new AndOrLatch();
+		latch.trigger(0b0, 0b0);
+		expect(latch.output).toBe(0b0);
+	});
+
+	test("Latch remembers its value", () => {
+		const latch = new AndOrLatch();
+
+		(() => {
+			// source 1
+			latch.trigger(0b1, 0b0);
+			latch.trigger(0b0, 0b0);
+		})();
+
+		(() => {
+			// source 2
+			latch.trigger(0b0, 0b0);
+			latch.trigger(0b1, 0b0);
+		})();
+
+		expect(latch.output).toBe(0b1);
+	});
+
+	test("Resetting latch outputs 0", () => {
+		const latch = new AndOrLatch();
+
+		latch.trigger(0b1, 0b1);
+		expect(latch.output).toBe(0b0);
+
+		latch.trigger(0b0, 0b1);
+		expect(latch.output).toBe(0b0);
+	});
+});