initial commit

.gitignore

@@ -0,0 +1,2 @@
+dist
+node_modules

.prettierrc

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+{
+    "useTabs": true,
+    "trailingComma": "all"
+}

package-lock.json

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+{
+  "name": "enigma-machine",
+  "version": "1.0.0",
+  "lockfileVersion": 3,
+  "requires": true,
+  "packages": {
+    "": {
+      "name": "enigma-machine",
+      "version": "1.0.0",
+      "license": "ISC",
+      "devDependencies": {
+        "@types/node": "^24.0.8"
+      }
+    },
+    "node_modules/@types/node": {
+      "version": "24.0.8",
+      "resolved": "https://registry.npmjs.org/@types/node/-/node-24.0.8.tgz",
+      "integrity": "sha512-WytNrFSgWO/esSH9NbpWUfTMGQwCGIKfCmNlmFDNiI5gGhgMmEA+V1AEvKLeBNvvtBnailJtkrEa2OIISwrVAA==",
+      "dev": true,
+      "license": "MIT",
+      "dependencies": {
+        "undici-types": "~7.8.0"
+      }
+    },
+    "node_modules/undici-types": {
+      "version": "7.8.0",
+      "resolved": "https://registry.npmjs.org/undici-types/-/undici-types-7.8.0.tgz",
+      "integrity": "sha512-9UJ2xGDvQ43tYyVMpuHlsgApydB8ZKfVYTsLDhXkFL/6gfkp+U8xTGdh8pMJv1SpZna0zxG1DwsKZsreLbXBxw==",
+      "dev": true,
+      "license": "MIT"
+    }
+  }
+}

package.json

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+{
+  "name": "enigma-machine",
+  "version": "1.0.0",
+  "main": "index.js",
+  "scripts": {
+    "test": "echo \"Error: no test specified\" && exit 1"
+  },
+  "author": "",
+  "license": "ISC",
+  "description": "",
+  "devDependencies": {
+    "@types/node": "^24.0.8"
+  }
+}

reflectors.csv

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+A,EJMZALYXVBWFCRQUONTSPIKHGD 		
+B,YRUHQSLDPXNGOKMIEBFZCWVJAT 		
+C,FVPJIAOYEDRZXWGCTKUQSBNMHL 		
+B Thin,ENKQAUYWJICOPBLMDXZVFTHRGS
+C Thin,RDOBJNTKVEHMLFCWZAXGYIPSUQ

rotors.csv

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+I,EKMFLGDQVZNTOWYHXUSPAIBRCJ,R
+II,AJDKSIRUXBLHWTMCQGZNPYFVOE,F
+III,BDFHJLCPRTXVZNYEIWGAKMUSQO,W
+IV,ESOVPZJAYQUIRHXLNFTGKDCMWB,K
+V,VZBRGITYUPSDNHLXAWMJQOFECK,A
+VI,JPGVOUMFYQBENHZRDKASXLICTW,AN
+VII,NZJHGRCXMYSWBOUFAIVLPEKQDT,AN
+VIII,FKQHTLXOCBJSPDZRAMEWNIUYGV,AN
+Beta,LEYJVCNIXWPBQMDRTAKZGFUHOS,
+Gamma,FSOKANUERHMBTIYCWLQPZXVGJD,

src/index.ts

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+import { Machine } from "./machine";
+
+const machine = new Machine("A", "I", "II", "III");
+
+console.log(machine.input("THISISAMESSAGEFORYOU"));
+console.log("rings", machine.rings());

src/loadComponentData.ts

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+import fs from "node:fs";
+
+export type RotorValues = {
+	name: string;
+	values: string[];
+	turnovers: string[];
+};
+
+export type ReflectorValues = {
+	name: string;
+	reflector: Map<string, string>;
+};
+
+function loadFile(filename: string) {
+	const data = fs.readFileSync(filename, "utf-8");
+	let row: string[] = [];
+	const table: string[][] = [];
+	let cell = "";
+
+	for (const char of data) {
+		if (char !== "," && char !== "\n") {
+			cell += char;
+		} else {
+			row.push(cell);
+			cell = "";
+
+			if (char === "\n") {
+				table.push(row);
+				row = [];
+			}
+		}
+	}
+
+	// if the file ends in a line break, this isn't needed but if it doesn't, then there
+	// is a rotor hanging out at the end that still needs to be added.
+	if (row.length > 0) {
+		row.push(cell);
+		table.push(row);
+	}
+
+	return table;
+}
+
+export function buildRotors(filename: string) {
+	const rotors: RotorValues[] = [];
+	const table = loadFile(filename);
+
+	for (const [name, valueString, turnovers] of table) {
+		rotors.push({
+			name,
+			values: valueString.split(""),
+			turnovers: turnovers.split(""),
+		});
+	}
+
+	return rotors;
+}
+
+export function buildReflectors(filename: string) {
+	const reflectors: ReflectorValues[] = [];
+	const table = loadFile(filename);
+
+	for (const [name, valueString] of table) {
+		const values = valueString.split("");
+		const reflector = { name, reflector: new Map() };
+
+		for (let i = 0; i < values.length; i++) {
+			const a = String.fromCharCode("A".charCodeAt(0) + i);
+			const b = values[i];
+
+			reflector.reflector.set(a, b);
+			reflector.reflector.set(b, a);
+		}
+
+		reflectors.push(reflector);
+	}
+
+	return reflectors;
+}

src/machine.ts

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+import {
+	buildReflectors,
+	buildRotors,
+	ReflectorValues,
+	RotorValues,
+} from "./loadComponentData";
+import { Plugboard } from "./plugboard";
+import { Rotor } from "./rotors";
+import { checkCharacter } from "./validation";
+
+const rotors = buildRotors("rotors.csv");
+const reflectors = buildReflectors("reflectors.csv");
+
+export class Machine {
+	plugboard: Plugboard;
+	reflector: ReflectorValues;
+	rotors: Rotor[];
+
+	constructor(reflector: string, first: string, second: string, third: string) {
+		this.plugboard = new Plugboard();
+		this.reflector = getComponent(reflectors, reflector);
+
+		this.rotors = [];
+		this.rotors.push(getRotor(getComponent(rotors, first)));
+		this.rotors.push(getRotor(getComponent(rotors, second)));
+		this.rotors.push(getRotor(getComponent(rotors, third)));
+	}
+
+	rings(): string[] {
+		return this.rotors.map((r) => r.position());
+	}
+
+	stecker(one: string, two: string) {
+		this.plugboard.stecker(one, two);
+	}
+
+	input(message: string): string {
+		let output = "";
+		for (let char of message) {
+			checkCharacter(char, "character");
+			let turnover = true;
+
+			// plugboard, first pass
+			let scrambled = this.plugboard.in(char);
+
+			// rotors, first pass (in)
+			for (const rotor of this.rotors) {
+				if (turnover) {
+					turnover = rotor.rotate();
+				}
+
+				scrambled = rotor.in(scrambled);
+			}
+
+			// reflector
+			scrambled = this.reflector.reflector.get(scrambled)!;
+
+			// rotors, second pass (out)
+			for (let i = this.rotors.length - 1; i >= 0; i--) {
+				const rotor = this.rotors[i];
+				scrambled = rotor.out(scrambled);
+			}
+
+			// plugboard, second pass
+			output += this.plugboard.in(scrambled);
+		}
+
+		return output;
+	}
+}
+
+function getRotor({ name, values, turnovers }: RotorValues) {
+	return new Rotor(name, values, turnovers, 0);
+}
+
+function getComponent<T extends { name: string }>(
+	components: T[],
+	componentName: string,
+): T {
+	const component = components.find(({ name }) => name === componentName);
+	if (!component) throw new Error(`unknown reflector: ${component}`);
+
+	return component;
+}

src/plugboard.ts

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+import { checkCharacter } from "./validation";
+
+export class Plugboard {
+	links: Map<string, string>;
+
+	constructor() {
+		this.links = new Map();
+	}
+
+	stecker(a: string, b: string) {
+		checkCharacter(a, "a");
+		checkCharacter(b, "b");
+
+		if (this.links.has(a) || this.links.has(b)) {
+			throw new Error("one of the provided letters is already mapped");
+		}
+
+		this.links.set(a, b);
+		this.links.set(b, a);
+	}
+
+	unlink(a: string) {
+		checkCharacter(a, "a");
+
+		if (!this.links.has(a)) return;
+
+		const b = this.links.get(a)!;
+
+		this.links.delete(a);
+		this.links.delete(b);
+	}
+
+	in(char: string) {
+		return this.links.get(char) ?? char;
+	}
+}

src/rotors.ts

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+import { checkCharacter } from "./validation";
+
+export class Rotor {
+	name: string;
+	offset: number;
+	values: string[];
+	turnovers: string[];
+
+	constructor(
+		name: string,
+		values: string[],
+		turnovers: string[],
+		offset: number = 0,
+	) {
+		this.name = name;
+		this.offset = offset;
+		this.values = values;
+		this.turnovers = turnovers;
+	}
+
+	rotate(times: number = 1): boolean {
+		if (times < 0) {
+			throw new Error("offset must be positive");
+		}
+
+		if (!Number.isInteger(times)) {
+			throw new Error("offset must be an integer");
+		}
+
+		const char = this.values[this.offset];
+		const turnover = this.turnovers.includes(char);
+
+		this.offset += times;
+		this.offset %= 26;
+
+		return turnover;
+	}
+
+	position(): string {
+		return String.fromCharCode("A".charCodeAt(0) + this.offset);
+	}
+
+	in(pos: string): string {
+		checkCharacter(pos, "position");
+
+		const posNum = pos.charCodeAt(0);
+		const input = (posNum - "A".charCodeAt(0) + this.offset) % 26;
+		return this.values[input];
+	}
+
+	out(pos: string): string {
+		checkCharacter(pos, "position");
+
+		const i = this.values.findIndex((char) => char === pos);
+		const str = String.fromCharCode(
+			"A".charCodeAt(0) + ((i + this.offset) % 26),
+		);
+
+		return str;
+	}
+}

src/validation.ts

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+export function checkCharacter(char: string, varName: string) {
+	const a = "A".charCodeAt(0);
+	const z = "Z".charCodeAt(0);
+	const posNum = char.charCodeAt(0);
+
+	if (char.length !== 1)
+		throw new Error(`${varName} should be single character`);
+
+	if (posNum < a || posNum > z) {
+		throw new Error(`${varName} should be between A and Z`);
+	}
+}

tsconfig.json

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+{
+  "compilerOptions": {
+    /* Visit https://aka.ms/tsconfig to read more about this file */
+
+    /* Projects */
+    // "incremental": true,                              /* Save .tsbuildinfo files to allow for incremental compilation of projects. */
+    // "composite": true,                                /* Enable constraints that allow a TypeScript project to be used with project references. */
+    // "tsBuildInfoFile": "./.tsbuildinfo",              /* Specify the path to .tsbuildinfo incremental compilation file. */
+    // "disableSourceOfProjectReferenceRedirect": true,  /* Disable preferring source files instead of declaration files when referencing composite projects. */
+    // "disableSolutionSearching": true,                 /* Opt a project out of multi-project reference checking when editing. */
+    // "disableReferencedProjectLoad": true,             /* Reduce the number of projects loaded automatically by TypeScript. */
+
+    /* Language and Environment */
+    "target": "es2016",                                  /* Set the JavaScript language version for emitted JavaScript and include compatible library declarations. */
+    // "lib": [],                                        /* Specify a set of bundled library declaration files that describe the target runtime environment. */
+    // "jsx": "preserve",                                /* Specify what JSX code is generated. */
+    // "experimentalDecorators": true,                   /* Enable experimental support for legacy experimental decorators. */
+    // "emitDecoratorMetadata": true,                    /* Emit design-type metadata for decorated declarations in source files. */
+    // "jsxFactory": "",                                 /* Specify the JSX factory function used when targeting React JSX emit, e.g. 'React.createElement' or 'h'. */
+    // "jsxFragmentFactory": "",                         /* Specify the JSX Fragment reference used for fragments when targeting React JSX emit e.g. 'React.Fragment' or 'Fragment'. */
+    // "jsxImportSource": "",                            /* Specify module specifier used to import the JSX factory functions when using 'jsx: react-jsx*'. */
+    // "reactNamespace": "",                             /* Specify the object invoked for 'createElement'. This only applies when targeting 'react' JSX emit. */
+    // "noLib": true,                                    /* Disable including any library files, including the default lib.d.ts. */
+    // "useDefineForClassFields": true,                  /* Emit ECMAScript-standard-compliant class fields. */
+    // "moduleDetection": "auto",                        /* Control what method is used to detect module-format JS files. */
+
+    /* Modules */
+    "module": "commonjs",                                /* Specify what module code is generated. */
+    "rootDir": "./src",                                  /* Specify the root folder within your source files. */
+    // "moduleResolution": "node10",                     /* Specify how TypeScript looks up a file from a given module specifier. */
+    // "baseUrl": "./",                                  /* Specify the base directory to resolve non-relative module names. */
+    // "paths": {},                                      /* Specify a set of entries that re-map imports to additional lookup locations. */
+    // "rootDirs": [],                                   /* Allow multiple folders to be treated as one when resolving modules. */
+    // "typeRoots": [],                                  /* Specify multiple folders that act like './node_modules/@types'. */
+    // "types": [],                                      /* Specify type package names to be included without being referenced in a source file. */
+    // "allowUmdGlobalAccess": true,                     /* Allow accessing UMD globals from modules. */
+    // "moduleSuffixes": [],                             /* List of file name suffixes to search when resolving a module. */
+    // "allowImportingTsExtensions": true,               /* Allow imports to include TypeScript file extensions. Requires '--moduleResolution bundler' and either '--noEmit' or '--emitDeclarationOnly' to be set. */
+    // "rewriteRelativeImportExtensions": true,          /* Rewrite '.ts', '.tsx', '.mts', and '.cts' file extensions in relative import paths to their JavaScript equivalent in output files. */
+    // "resolvePackageJsonExports": true,                /* Use the package.json 'exports' field when resolving package imports. */
+    // "resolvePackageJsonImports": true,                /* Use the package.json 'imports' field when resolving imports. */
+    // "customConditions": [],                           /* Conditions to set in addition to the resolver-specific defaults when resolving imports. */
+    // "noUncheckedSideEffectImports": true,             /* Check side effect imports. */
+    // "resolveJsonModule": true,                        /* Enable importing .json files. */
+    // "allowArbitraryExtensions": true,                 /* Enable importing files with any extension, provided a declaration file is present. */
+    // "noResolve": true,                                /* Disallow 'import's, 'require's or '<reference>'s from expanding the number of files TypeScript should add to a project. */
+
+    /* JavaScript Support */
+    // "allowJs": true,                                  /* Allow JavaScript files to be a part of your program. Use the 'checkJS' option to get errors from these files. */
+    // "checkJs": true,                                  /* Enable error reporting in type-checked JavaScript files. */
+    // "maxNodeModuleJsDepth": 1,                        /* Specify the maximum folder depth used for checking JavaScript files from 'node_modules'. Only applicable with 'allowJs'. */
+
+    /* Emit */
+    // "declaration": true,                              /* Generate .d.ts files from TypeScript and JavaScript files in your project. */
+    // "declarationMap": true,                           /* Create sourcemaps for d.ts files. */
+    // "emitDeclarationOnly": true,                      /* Only output d.ts files and not JavaScript files. */
+    // "sourceMap": true,                                /* Create source map files for emitted JavaScript files. */
+    // "inlineSourceMap": true,                          /* Include sourcemap files inside the emitted JavaScript. */
+    // "noEmit": true,                                   /* Disable emitting files from a compilation. */
+    // "outFile": "./",                                  /* Specify a file that bundles all outputs into one JavaScript file. If 'declaration' is true, also designates a file that bundles all .d.ts output. */
+    "outDir": "./dist",                                  /* Specify an output folder for all emitted files. */
+    // "removeComments": true,                           /* Disable emitting comments. */
+    // "importHelpers": true,                            /* Allow importing helper functions from tslib once per project, instead of including them per-file. */
+    // "downlevelIteration": true,                       /* Emit more compliant, but verbose and less performant JavaScript for iteration. */
+    // "sourceRoot": "",                                 /* Specify the root path for debuggers to find the reference source code. */
+    // "mapRoot": "",                                    /* Specify the location where debugger should locate map files instead of generated locations. */
+    // "inlineSources": true,                            /* Include source code in the sourcemaps inside the emitted JavaScript. */
+    // "emitBOM": true,                                  /* Emit a UTF-8 Byte Order Mark (BOM) in the beginning of output files. */
+    // "newLine": "crlf",                                /* Set the newline character for emitting files. */
+    // "stripInternal": true,                            /* Disable emitting declarations that have '@internal' in their JSDoc comments. */
+    // "noEmitHelpers": true,                            /* Disable generating custom helper functions like '__extends' in compiled output. */
+    // "noEmitOnError": true,                            /* Disable emitting files if any type checking errors are reported. */
+    // "preserveConstEnums": true,                       /* Disable erasing 'const enum' declarations in generated code. */
+    // "declarationDir": "./",                           /* Specify the output directory for generated declaration files. */
+
+    /* Interop Constraints */
+    // "isolatedModules": true,                          /* Ensure that each file can be safely transpiled without relying on other imports. */
+    // "verbatimModuleSyntax": true,                     /* Do not transform or elide any imports or exports not marked as type-only, ensuring they are written in the output file's format based on the 'module' setting. */
+    // "isolatedDeclarations": true,                     /* Require sufficient annotation on exports so other tools can trivially generate declaration files. */
+    // "allowSyntheticDefaultImports": true,             /* Allow 'import x from y' when a module doesn't have a default export. */
+    "esModuleInterop": true,                             /* Emit additional JavaScript to ease support for importing CommonJS modules. This enables 'allowSyntheticDefaultImports' for type compatibility. */
+    // "preserveSymlinks": true,                         /* Disable resolving symlinks to their realpath. This correlates to the same flag in node. */
+    "forceConsistentCasingInFileNames": true,            /* Ensure that casing is correct in imports. */
+
+    /* Type Checking */
+    "strict": true,                                      /* Enable all strict type-checking options. */
+    // "noImplicitAny": true,                            /* Enable error reporting for expressions and declarations with an implied 'any' type. */
+    // "strictNullChecks": true,                         /* When type checking, take into account 'null' and 'undefined'. */
+    // "strictFunctionTypes": true,                      /* When assigning functions, check to ensure parameters and the return values are subtype-compatible. */
+    // "strictBindCallApply": true,                      /* Check that the arguments for 'bind', 'call', and 'apply' methods match the original function. */
+    // "strictPropertyInitialization": true,             /* Check for class properties that are declared but not set in the constructor. */
+    // "strictBuiltinIteratorReturn": true,              /* Built-in iterators are instantiated with a 'TReturn' type of 'undefined' instead of 'any'. */
+    // "noImplicitThis": true,                           /* Enable error reporting when 'this' is given the type 'any'. */
+    // "useUnknownInCatchVariables": true,               /* Default catch clause variables as 'unknown' instead of 'any'. */
+    // "alwaysStrict": true,                             /* Ensure 'use strict' is always emitted. */
+    // "noUnusedLocals": true,                           /* Enable error reporting when local variables aren't read. */
+    // "noUnusedParameters": true,                       /* Raise an error when a function parameter isn't read. */
+    // "exactOptionalPropertyTypes": true,               /* Interpret optional property types as written, rather than adding 'undefined'. */
+    // "noImplicitReturns": true,                        /* Enable error reporting for codepaths that do not explicitly return in a function. */
+    // "noFallthroughCasesInSwitch": true,               /* Enable error reporting for fallthrough cases in switch statements. */
+    // "noUncheckedIndexedAccess": true,                 /* Add 'undefined' to a type when accessed using an index. */
+    // "noImplicitOverride": true,                       /* Ensure overriding members in derived classes are marked with an override modifier. */
+    // "noPropertyAccessFromIndexSignature": true,       /* Enforces using indexed accessors for keys declared using an indexed type. */
+    // "allowUnusedLabels": true,                        /* Disable error reporting for unused labels. */
+    // "allowUnreachableCode": true,                     /* Disable error reporting for unreachable code. */
+
+    /* Completeness */
+    // "skipDefaultLibCheck": true,                      /* Skip type checking .d.ts files that are included with TypeScript. */
+    "skipLibCheck": true                                 /* Skip type checking all .d.ts files. */
+  }
+}