Package setup, parser and a utility function

.editorconfig

@@ -0,0 +1,10 @@
+root = true
+
+[*]
+charset = utf-8
+indent_style = space
+indent_size = 4
+end_of_line = lf
+insert_final_newline = true
+trim_trailing_whitespace = true
+

.eslintignore

@@ -0,0 +1,2 @@
+**/build/
+**/node_modules/

.eslintrc.json

@@ -0,0 +1,52 @@
+{
+    "extends": [
+        "@generalprotocols/eslint-config/typescript",
+        "plugin:prettier/recommended"
+    ],
+    "parserOptions": {
+        "ecmaVersion": 2020,
+        "project": "./tsconfig.json",
+        "sourceType": "module"
+    },
+    "rules": {
+        "@typescript-eslint/no-unused-vars": [
+            "error",
+            {
+                "argsIgnorePattern": "^_",
+                "destructuredArrayIgnorePattern": "^_"
+            }
+        ],
+        "import/extensions": [
+            "error",
+            {
+                "js": "always"
+            }
+        ],
+        "import/no-internal-modules": [
+            "error"
+        ],
+        "max-len": [
+            "error",
+            {
+                "code": 150,
+                "ignoreUrls": true,
+                "ignoreStrings": true,
+                "ignoreTemplateLiterals": true,
+                "ignoreComments": true
+            }
+        ],
+        "no-unused-vars": [
+            "error",
+            {
+                "argsIgnorePattern": "^_",
+                "destructuredArrayIgnorePattern": "^_"
+            }
+        ],
+        "object-curly-newline": [
+            "error",
+            {
+                "multiline": true
+            }
+        ]
+    }
+}

.gitignore

@@ -0,0 +1,21 @@
+.vscode/
+build/
+build/**
+node_modules/
+yarn.lock
+yarn-error.log
+
+.DS_Store
+
+*.js
+*.js.map
+*.d.ts
+*.d.ts.map
+*.tsbuildinfo
+
+# Generated files
+src/parser/xo-template.schema.json
+src/parser/ajv/validate-xo-template.js
+
+# Exception: include generate-schema.js
+!scripts/generate-schema.js

.prettierrc.json

@@ -0,0 +1,7 @@
+{
+    "printWidth": 150,
+    "useTabs": false,
+    "tabWidth": 4,
+    "singleQuote": true,
+    "semi": true
+}

README.md

@@ -0,0 +1,24 @@
+# @xo-cash/utils
+
+XO utilities and parser
+
+## Installation
+
+```bash
+npm install @xo-cash/utils
+```
+
+## Usage
+
+```typescript
+import { scriptToScriptHash } from '@xo-cash/utils';
+```
+
+## Links
+
+- [Repository](https://gitlab.com/GeneralProtocols/xo/utils)
+- [Issues](https://gitlab.com/GeneralProtocols/xo/utils/issues)
+
+## License
+
+MIT

package.json

@@ -0,0 +1,59 @@
+{
+    "name": "@xo-cash/utils",
+    "version": "0.0.1",
+    "description": "XO Cash utilities",
+    "type": "module",
+    "exports": {
+        ".": "./build/index.js"
+    },
+    "types": "./build/index.d.ts",
+    "sideEffects": false,
+    "scripts": {
+        "build": "npm run clean && tsc",
+        "clean": "del-cli ./build",
+        "docs": "typedoc --hideGenerator --categorizeByGroup",
+        "lint": "eslint . --ext .ts",
+        "lint:fix": "eslint . --ext .ts --fix",
+        "prebuild": "node scripts/generate-schema.js",
+        "prepublishOnly": "npm run build",
+        "syntax": "tsc --noEmit"
+    },
+    "files": [
+        "build"
+    ],
+    "repository": {
+        "type": "git",
+        "url": "git+https://gitlab.com/GeneralProtocols/xo/utils.git"
+    },
+    "author": "GeneralProtocols",
+    "license": "MIT",
+    "bugs": {
+        "url": "https://gitlab.com/GeneralProtocols/xo/utils/issues"
+    },
+    "homepage": "https://gitlab.com/GeneralProtocols/xo/utils#readme",
+    "keywords": [
+        "bitcoin cash",
+        "xo cash"
+    ],
+    "dependencies": {
+        "@bitauth/libauth": "^3.1.0-next.8",
+        "@xo-cash/types": "file:../types"
+    },
+    "devDependencies": {
+        "@generalprotocols/eslint-config": "^1.0.1",
+        "@types/node": "^20.10.0",
+        "ajv-cli": "^5.0.0",
+        "del-cli": "^7.0.0",
+        "eslint": "^8.57.1",
+        "eslint-config-prettier": "^10.1.8",
+        "eslint-plugin-prettier": "^5.5.4",
+        "prettier": "^3.6.2",
+        "ts-json-schema-generator": "^2.4.0",
+        "typedoc": "^0.28.15",
+        "typedoc-plugin-coverage": "^4.0.2",
+        "typescript": "^5.3.2"
+    },
+    "engines": {
+        "node": ">=18.0.0"
+    }
+}

scripts/generate-schema.js

@@ -0,0 +1,63 @@
+#!/usr/bin/env node
+
+import { execSync } from 'child_process';
+import { readFileSync, writeFileSync } from 'fs';
+import { fileURLToPath } from 'url';
+import { dirname, join } from 'path';
+
+const __filename = fileURLToPath(import.meta.url);
+const __dirname = dirname(__filename);
+const rootDir = join(__dirname, '..');
+
+// exec helper
+function exec(command, options = {}) {
+	const defaultOptions = {
+		stdio: 'inherit',
+		cwd: rootDir,
+		shell: true,
+		...options,
+	};
+	return execSync(command, defaultOptions);
+}
+
+try {
+
+	const schemaPath = join(rootDir, 'src/parser/xo-template.schema.json');
+	const validatorPath = join(rootDir, 'src/parser/ajv/validate-xo-template.js');
+	const tsconfigPath = join(rootDir, 'tsconfig.json');
+	const templatePath = join(
+		rootDir,
+		'node_modules/@xo-cash/types/build/template.d.ts',
+	);
+
+	// Generate schema JSON (write to file directly instead of shell redirection)
+	const schemaContent = execSync(
+		`ts-json-schema-generator --no-ref-encode --tsconfig "${tsconfigPath}" --path "${templatePath}" --type "XOTemplate"`,
+		{ encoding: 'utf8', cwd: rootDir },
+	);
+	writeFileSync(schemaPath, schemaContent, 'utf8');
+
+	// Compile validator with AJV
+	exec(
+		`ajv compile -s "${schemaPath}" --allowUnionTypes -o "${validatorPath}"`,
+	);
+
+	// Transform the generated validator code
+	let code = readFileSync(validatorPath, 'utf8');
+
+	code = code
+		.replace(
+			/"use strict";module\.exports = [^;]+;module\.exports\.default = [^;]+;/,
+			'export default validate20;',
+		)
+		.replace(/;const /g, ';\nconst ')
+		.replace(/;function /g, ';\nfunction ')
+		.replace(/\}function /g, '}\nfunction ');
+
+	writeFileSync(validatorPath, code, 'utf8');
+
+	console.log('Schema generation complete!');
+} catch (error) {
+	console.error('Error generating schema:', error.message);
+	process.exit(1);
+}

src/index.ts

@@ -0,0 +1,3 @@
+export * from './parser/xo-template.js';
+export * from './parser/errors.js';
+export * from './script.js';

src/parser/ajv/ajv-types.ts

@@ -0,0 +1,33 @@
+/**
+ * This code is inspired by and adapted from:
+ * https://github.com/bitauth/libauth
+ */
+export type AjvError<Keyword = string, Params = { [paramName: string]: number | string }> = {
+	keyword: Keyword;
+	instancePath: string;
+	schemaPath: string;
+	params: Params;
+	message: string;
+};
+
+export type XOAjvError =
+	| AjvError<'additionalProperties', { additionalProperty: string }>
+	| AjvError<'required', { missingProperty: string }>
+	| AjvError<'type', { type: string }>;
+
+/**
+ * Note: these types cover only XO use cases; other `ajv` error types are
+ * possible using other settings.
+ */
+export type AjvValidator<T = unknown> = {
+	(
+		data: unknown,
+		dataCxt?: {
+			instancePath?: string;
+			parentData: any;
+			parentDataProperty: any;
+			rootData?: any;
+		},
+	): data is T;
+	errors?: XOAjvError[] | null;
+};

src/parser/ajv/ajv-utils.ts

@@ -0,0 +1,33 @@
+/* eslint-disable implicit-arrow-linebreak, @typescript-eslint/explicit-function-return-type, newline-before-return */
+/**
+ * This code is inspired by and adapted from:
+ * https://github.com/bitauth/libauth
+ */
+import { lossyNormalize } from '@bitauth/libauth';
+import xoTemplateValidator from './validate-xo-template.js';
+import type { AjvValidator, XOAjvError } from './ajv-types.js';
+
+const avjErrorsToDescription = (errors: XOAjvError[]): string =>
+	// TODO: translate instancePath
+	errors.map((error) => `${error.instancePath}: ${error.message}`).join(',');
+
+/**
+ * Given an untrusted JSON string or object and an AJV validator, verify that
+ * the untrusted value is of the expected shape. Note, this method first
+ * normalizes all characters in the input using `Normalization Form KC`
+ * (Compatibility Decomposition, followed by Canonical Composition).
+ */
+export const ajvStandaloneJsonParse = <T>(untrustedJsonOrObject: unknown, validator: AjvValidator<T>) => {
+	try {
+		const stringified = typeof untrustedJsonOrObject === 'string' ? untrustedJsonOrObject : JSON.stringify(untrustedJsonOrObject);
+		const normalized = lossyNormalize(stringified);
+		const parsed = JSON.parse(normalized) as unknown;
+		if (validator(parsed)) {
+			return parsed;
+		}
+		// @ts-ignore
+		return avjErrorsToDescription(xoTemplateValidator.errors!);
+	} catch (e) {
+		return `Invalid JSON. ${String(e)}`;
+	}
+};

src/parser/errors.ts

@@ -0,0 +1,6 @@
+export class TemplateImportFailedError extends Error {
+	constructor(templateIdentifier: string) {
+		const message = `Template import failed: ${templateIdentifier}`;
+		super(message);
+	}
+}

src/parser/xo-template.ts

@@ -0,0 +1,43 @@
+/**
+ * This code is inspired by and adapted from:
+ * https://github.com/bitauth/libauth
+ */
+import type { XOTemplate } from '@xo-cash/types';
+import { ajvStandaloneJsonParse } from './ajv/ajv-utils.js';
+// eslint-disable-next-line import/no-internal-modules
+import xoTemplateValidator from './ajv/validate-xo-template.js';
+import { TemplateImportFailedError } from './errors.js';
+
+/**
+ * Safely parse and validate a wallet template, returning either an
+ * error message as a string or a valid {@link XOTemplate}. The
+ * template may be provided either as an untrusted JSON string or as a
+ * pre-parsed object.
+ *
+ * This method validates both the structure and the contents of a template:
+ * - All properties and sub-properties are verified to be of the expected type.
+ * - The template contains no unknown properties.
+ * - The ID of each entity, script, and scenario is confirmed to be unique.
+ * - Script IDs referenced by entities and other scripts (via `unlocks`) are
+ *   confirmed to exist.
+ * - The derivation paths of each HdKey are validated against each other.
+ *
+ * This method does not validate the CashAssembly contents of scripts (by
+ * attempting compilation, evaluating {@link XOTemplateScriptTest}s,
+ * or testing scenario generation).
+ *
+ * @param untrustedJsonOrObject - the JSON string or object to validate as a
+ * XO template
+ */
+export const sanitizeTemplate = (untrustedJsonOrObject: unknown): XOTemplate => {
+	const template = ajvStandaloneJsonParse<XOTemplate>(
+		untrustedJsonOrObject,
+		// @ts-ignore
+		xoTemplateValidator,
+	);
+	if (typeof template === 'string') {
+		throw new TemplateImportFailedError(template);
+	}
+
+	return template;
+};

src/script.ts

@@ -0,0 +1,14 @@
+import { binToHex, instantiateSha256 } from '@bitauth/libauth';
+
+/**
+ * Converts a script to a scripthash.
+ * @param {Uint8Array} script - The script to convert.
+ * @returns {Promise<string>} The scripthash as a hexadecimal string.
+ */
+export const scriptToScriptHash = async (script: Uint8Array): Promise<string> => {
+	const sha256 = await instantiateSha256();
+	const hash = sha256.hash(script);
+	const reversed = hash.reverse();
+
+	return binToHex(reversed);
+};

tsconfig.json

@@ -0,0 +1,26 @@
+{
+    "compilerOptions": {
+        "target": "ES2022",
+        "module": "NodeNext",
+        "moduleResolution": "NodeNext",
+        "rootDir": "src",
+        "outDir": "build",
+        "incremental": true,
+        "tsBuildInfoFile": "./build/.tsbuildinfo",
+        "esModuleInterop": true,
+        "resolveJsonModule": true,
+        "declaration": true,
+        "declarationMap": true,
+        "sourceMap": true,
+        "skipLibCheck": true,
+        "strict": true,
+        "allowJs": true,
+        "strictPropertyInitialization": false,
+        "traceResolution": false,
+        "listEmittedFiles": false,
+        "listFiles": false,
+        "pretty": true
+    },
+    "exclude": ["node_modules", "build", "scripts"],
+    "compileOnSave": false
+}