pybricksMicropython/lib: add module

This creates a new module for dealing with stuff specific to Pybricks
MicroPython.

src/pybricksMicropython/lib.test.ts

@@ -0,0 +1,54 @@
+// SPDX-License-Identifier: MIT
+// Copyright (c) 2022 The Pybricks Authors
+
+import { FileNameValidationResult, pythonFileExtension, validateFileName } from './lib';
+
+describe('validateFileName', () => {
+    it('should allow file names with underscores', () => {
+        expect(validateFileName('file_name', pythonFileExtension, [])).toBe(
+            FileNameValidationResult.IsOk,
+        );
+    });
+
+    it('should allow file names with dashes', () => {
+        expect(validateFileName('file-name', pythonFileExtension, [])).toBe(
+            FileNameValidationResult.IsOk,
+        );
+    });
+
+    it('should not allow empty strings', () => {
+        expect(validateFileName('', pythonFileExtension, [])).toBe(
+            FileNameValidationResult.IsEmpty,
+        );
+    });
+
+    it('should not allow file names with spaces', () => {
+        expect(validateFileName('file name', pythonFileExtension, [])).toBe(
+            FileNameValidationResult.HasSpaces,
+        );
+    });
+
+    it('should not allow file names that start with numbers', () => {
+        expect(validateFileName('1test', pythonFileExtension, [])).toBe(
+            FileNameValidationResult.HasInvalidFirstCharacter,
+        );
+    });
+
+    it('should not allow file names with symbols', () => {
+        expect(validateFileName('test$', pythonFileExtension, [])).toBe(
+            FileNameValidationResult.HasInvalidCharacters,
+        );
+    });
+
+    it('it should not allow file names that include the file extension', () => {
+        expect(validateFileName('test.py', pythonFileExtension, [])).toBe(
+            FileNameValidationResult.HasFileExtension,
+        );
+    });
+
+    it('should not allow file names that match existing files', () => {
+        expect(validateFileName('test', pythonFileExtension, ['test.py'])).toBe(
+            FileNameValidationResult.AlreadyExists,
+        );
+    });
+});

src/pybricksMicropython/lib.ts

@@ -0,0 +1,66 @@
+// SPDX-License-Identifier: MIT
+// Copyright (c) 2022 The Pybricks Authors
+
+/** The Python file extension ('.py') */
+export const pythonFileExtension = '.py';
+
+/** The Python file MIME type ('text/x-python') */
+export const pythonFileMimeType = 'text/x-python';
+
+/** File name validation results. */
+export enum FileNameValidationResult {
+    /** The file name is acceptable. */
+    IsOk,
+    /** The file name is an empty string. */
+    IsEmpty,
+    /** The file name contains spaces. */
+    HasSpaces,
+    /** The file name include the file file extension. */
+    HasFileExtension,
+    /** The first character is not a letter or underscore. */
+    HasInvalidFirstCharacter,
+    /** The file name has invalid characters. */
+    HasInvalidCharacters,
+    /** A file with the same name already exists. */
+    AlreadyExists,
+}
+
+/**
+ * Validates the file name according to a number of criteria.
+ *
+ * @param fileName The file name (without extension).
+ * @param extension The file extension (including ".").
+ * @param existingFiles List of existing files.
+ * @returns The result of the validation.
+ */
+export function validateFileName(
+    fileName: string,
+    extension: string,
+    existingFiles: ReadonlyArray<string>,
+): FileNameValidationResult {
+    if (existingFiles.includes(`${fileName}${extension}`)) {
+        return FileNameValidationResult.AlreadyExists;
+    }
+
+    if (fileName.length === 0) {
+        return FileNameValidationResult.IsEmpty;
+    }
+
+    if (fileName.match(/\s/)) {
+        return FileNameValidationResult.HasSpaces;
+    }
+
+    if (fileName.endsWith(extension)) {
+        return FileNameValidationResult.HasFileExtension;
+    }
+
+    if (!fileName.match(/^[a-zA-Z_]/)) {
+        return FileNameValidationResult.HasInvalidFirstCharacter;
+    }
+
+    if (!fileName.match(/^[a-zA-Z0-9_-]+$/)) {
+        return FileNameValidationResult.HasInvalidCharacters;
+    }
+
+    return FileNameValidationResult.IsOk;
+}