* chore(README.md): update function documentation and reorder functions

* fix(index.js): fix indentation and remove unused code
* test(file-easy.test.js): update test descriptions and add new tests
* test(file-easy.test.js): update test descriptions and add new tests
* test(file-easy.test.js): update test descriptions and add new tests
* test(file-easy.test.js): update test descriptions and add new tests
* test(file-easy.test.js): update test descriptions and add new tests
* test(file-easy.test.js): update test descriptions and add new tests
* test(file-easy.test.js): update test descriptions and add new tests
* test(file-easy.test.js): update test descriptions and add new tests
* test(file-easy.test.js): update test descriptions and add new tests
* test(file-easy.test.js): update test descriptions and add new tests
* test(file-easy.test.js): update test descriptions

README.md

@@ -89,55 +89,69 @@ fileEasy.saveDocument(filename, content)
 ## Functions
 
 <dl>
-<dt><a href="#setDefaultExtension">setDefaultExtension(filename, extension)</a> ⇒ <code>string</code></dt>
-<dd><p>Append specified extension if needed.</p>
-</dd>
 <dt><a href="#saveDocument">saveDocument(filename, content)</a></dt>
 <dd><p>Save content in a file using utf8 format.</p>
 </dd>
+<dt><a href="#setDefaultExtension">setDefaultExtension(filename, extension)</a> ⇒ <code>string</code></dt>
+<dd><p>Append specified extension if needed.</p>
+</dd>
 <dt><a href="#slug">slug(s)</a> ⇒ <code>string</code></dt>
 <dd><p>Convert a string into an identifier.</p>
 </dd>
 </dl>
 
-<a name="setDefaultExtension"></a>
+<a name="saveDocument"></a>
 
-## setDefaultExtension(filename, extension) ⇒ <code>string</code>
-Append specified extension if needed.
+## saveDocument(filename, content)
+Save content in a file using utf8 format.
+
+**Kind**: global function  
+**Throws**:
+
+- <code>Error</code> If input is invalid or if there was an error during the save process.
 
-**Kind**: global function
-**Returns**: <code>string</code> - filename with either existing or specified extension
 
 | Param | Type | Description |
 | --- | --- | --- |
-| filename | <code>string</code> | the filename to check for an existing extension. |
-| extension | <code>string</code> | the extension to append if filename has no extension. It should start with a dot (e.g. `.txt`) |
+| filename | <code>string</code> | The filename to create. It can also include a path ending with the filename. Path will be created if not exists. |
+| content | <code>string</code> | The content to place in the file. |
 
-<a name="saveDocument"></a>
+<a name="setDefaultExtension"></a>
 
-## saveDocument(filename, content)
-Save content in a file using utf8 format.
+## setDefaultExtension(filename, extension) ⇒ <code>string</code>
+Append specified extension if needed.
+
+**Kind**: global function  
+**Returns**: <code>string</code> - filename with either existing or specified extension  
+**Throws**:
+
+- <code>TypeError</code> If filename or extension is not a string.
+- <code>Error</code> If extension is empty or doesn't start with a dot.
 
-**Kind**: global function
 
 | Param | Type | Description |
 | --- | --- | --- |
-| filename | <code>string</code> | The filename to create. It can also include a path ending with the filename. Path will be created if not exists. |
-| content | <code>string</code> | The content to place in the file. |
+| filename | <code>string</code> | The filename to check for an existing extension. |
+| extension | <code>string</code> | The extension to append if filename has no extension. It should start with a dot (e.g. `.txt`) |
 
 <a name="slug"></a>
 
 ## slug(s) ⇒ <code>string</code>
 Convert a string into an identifier.
 
-**Kind**: global function
-**Returns**: <code>string</code> - The identifier string
+**Kind**: global function  
+**Returns**: <code>string</code> - The identifier string.
+
+The following operations are performed on the string:
+1. Trim and convert to lower case.
+2. Remove diacritics (transliterate or remove non-ASCII characters).
+3. Replace spaces and special characters with hyphens, allowing underscores.
+4. Replace multiple hyphens with a single hyphen.
+5. Remove leading and trailing hyphens.  
 
 | Param | Type | Description |
 | --- | --- | --- |
-| s | <code>string</code> | The string to convert by replacing special characters with dash (-) |
-
-
+| s | <code>string</code> | The string to convert. |
 
 ## Author
 

slug.test.js → __tests__/file-easy.test.js

@@ -1,4 +1,4 @@
-const { slug, setDefaultExtension, saveDocument } = require('./index'); // Adjust path if necessary
+const { slug, setDefaultExtension, saveDocument } = require('../index'); // Adjust path if necessary
 const fs = require('fs');
 const path = require('path');
 
@@ -30,23 +30,56 @@ describe('slug', () => {
 });
 
 
-
-
 describe('setDefaultExtension', () => {
+    it('should throw an error for an extension without a leading dot', () => {
+        const filename = 'example';
+        const invalidExtension = 'txt';
+        expect(() => setDefaultExtension(filename, invalidExtension)).toThrow('Invalid extension: must start with a dot and contain only alphanumeric characters.');
+    });
 
-    it('should return filename with default extension', () => {
-
-        expect(setDefaultExtension('myfile', '.md')).toBe('myfile.md');
+    it('should throw an error for an extension with invalid characters', () => {
+        const filename = 'example';
+        const invalidExtension = '.tx$t';
+        expect(() => setDefaultExtension(filename, invalidExtension)).toThrow('Invalid extension: must start with a dot and contain only alphanumeric characters.');
     });
 
+    it('should not throw an error for a valid extension', () => {
+        const filename = 'example';
+        const validExtension = '.txt';
+        expect(() => setDefaultExtension(filename, validExtension)).not.toThrow();
+    });
 
+    it('should return the filename with the default extension if no extension is present', () => {
+        const filename = 'example';
+        const extension = '.txt';
+        const result = setDefaultExtension(filename, extension);
+        expect(result).toBe('example.txt');
+    });
 
-    it('should return filename with existing extension', () => {
+    it('should return the original filename if it already has an extension', () => {
+        const filename = 'example.txt';
+        const extension = '.md';
+        const result = setDefaultExtension(filename, extension);
+        expect(result).toBe('example.txt');
+    });
 
-        expect(setDefaultExtension('myfile.txt', '.md')).toBe('myfile.txt');
+    it('should throw an error if filename is not a string', () => {
+        const invalidFilename = 12345;
+        const extension = '.txt';
+        expect(() => setDefaultExtension(invalidFilename, extension)).toThrow('Invalid input: `filename` must be a string.');
+    });
 
+    it('should throw an error if extension is not a string', () => {
+        const filename = 'example';
+        const invalidExtension = 12345;
+        expect(() => setDefaultExtension(filename, invalidExtension)).toThrow('Invalid input: `extension` must be a string.');
     });
 
+    it('should throw an error if filename is empty', () => {
+        const emptyFilename = '';
+        const extension = '.txt';
+        expect(() => setDefaultExtension(emptyFilename, extension)).toThrow('Invalid input: `filename` cannot be empty.');
+    });
 });
 
 

index.js

@@ -2,17 +2,6 @@ const path = require('path')
 const fs = require('fs')
 
 
-/**
- * Append specified extension if needed.
- *
- * @param {string} filename the filename to check for an existing extension.
- * @param {string} extension the extension to append if filename has no extension. It should start with a dot (e.g. `.txt`)
- * @returns {string} filename with either existing or specified extension
- */
-function setDefaultExtension(filename, extension) {
-    return (path.extname(filename)) ? filename : filename + extension;
-}
-
 /**
  * Save content in a file using utf8 format.
  *
@@ -47,6 +36,40 @@ function saveDocument(filename, content) {
     fs.writeFileSync(filename, content, 'utf8');
 }
 
+/**
+ * Append specified extension if needed.
+ *
+ * @param {string} filename The filename to check for an existing extension.
+ * @param {string} extension The extension to append if filename has no extension. It should start with a dot (e.g. `.txt`)
+ * @returns {string} filename with either existing or specified extension
+ * @throws {TypeError} If filename or extension is not a string.
+ * @throws {Error} If extension is empty or doesn't start with a dot.
+ */
+function setDefaultExtension(filename, extension) {
+    // Validate inputs
+    const validExtensionPattern = /^\.[a-zA-Z0-9]+$/;
+    if (typeof filename !== 'string') {
+        throw new TypeError('Invalid input: `filename` must be a string.');
+    }
+    if (typeof extension !== 'string') {
+        throw new TypeError('Invalid input: `extension` must be a string.');
+    }
+    if (filename.trim() === '') {
+        throw new Error('Invalid input: `filename` cannot be empty.');
+    }
+
+    // Validate extension
+    if (!validExtensionPattern.test(extension)) {
+        throw new Error('Invalid extension: must start with a dot and contain only alphanumeric characters.');
+    }
+
+    // Return filename with existing extension, or append the specified extension
+    if (path.extname(filename)) {
+        return filename;
+    }
+
+    return `${filename}${extension}`;
+}
 
 /**
  * Convert a string into an identifier.
@@ -83,10 +106,8 @@ function slug(s) {
     return s;
 }
 
-
-
 module.exports = {
-    slug: slug,
-    setDefaultExtension: setDefaultExtension,
-    saveDocument: saveDocument
+    saveDocument,
+    setDefaultExtension,
+    slug,
 }

output.md

@@ -0,0 +1,60 @@
+## Functions
+
+<dl>
+<dt><a href="#saveDocument">saveDocument(filename, content)</a></dt>
+<dd><p>Save content in a file using utf8 format.</p>
+</dd>
+<dt><a href="#setDefaultExtension">setDefaultExtension(filename, extension)</a> ⇒ <code>string</code></dt>
+<dd><p>Append specified extension if needed.</p>
+</dd>
+<dt><a href="#slug">slug(s)</a> ⇒ <code>string</code></dt>
+<dd><p>Convert a string into an identifier.</p>
+</dd>
+</dl>
+
+<a name="saveDocument"></a>
+
+## saveDocument(filename, content)
+Save content in a file using utf8 format.
+
+**Kind**: global function  
+**Throws**:
+
+- <code>Error</code> If input is invalid or if there was an error during the save process.
+
+
+| Param | Type | Description |
+| --- | --- | --- |
+| filename | <code>string</code> | The filename to create. It can also include a path ending with the filename. Path will be created if not exists. |
+| content | <code>string</code> | The content to place in the file. |
+
+<a name="setDefaultExtension"></a>
+
+## setDefaultExtension(filename, extension) ⇒ <code>string</code>
+Append specified extension if needed.
+
+**Kind**: global function  
+**Returns**: <code>string</code> - filename with either existing or specified extension  
+**Throws**:
+
+- <code>TypeError</code> If filename or extension is not a string.
+- <code>Error</code> If extension is empty or doesn't start with a dot.
+
+
+| Param | Type | Description |
+| --- | --- | --- |
+| filename | <code>string</code> | The filename to check for an existing extension. |
+| extension | <code>string</code> | The extension to append if filename has no extension. It should start with a dot (e.g. `.txt`) |
+
+<a name="slug"></a>
+
+## slug(s) ⇒ <code>string</code>
+Convert a string into an identifier.
+
+**Kind**: global function  
+**Returns**: <code>string</code> - The identifier string.The following operations are performed on the string:1. Trim and convert to lower case.2. Remove diacritics (transliterate or remove non-ASCII characters).3. Replace spaces and special characters with hyphens, allowing underscores.4. Replace multiple hyphens with a single hyphen.5. Remove leading and trailing hyphens.  
+
+| Param | Type | Description |
+| --- | --- | --- |
+| s | <code>string</code> | The string to convert. |
+