Fix tempy.file() always adds extension-dot . even if no extension…

… is given (#19)

Co-authored-by: Sindre Sorhus <sindresorhus@gmail.com>

index.js

@@ -8,19 +8,18 @@ const getPath = () => path.join(tempDir, uniqueString());
 
 module.exports.file = options => {
 	options = {
-		extension: '',
 		...options
 	};
 
 	if (options.name) {
-		if (options.extension) {
+		if (options.extension !== undefined && options.extension !== null) {
 			throw new Error('The `name` and `extension` options are mutually exclusive');
 		}
 
 		return path.join(module.exports.directory(), options.name);
 	}
 
-	return getPath() + '.' + options.extension.replace(/^\./, '');
+	return getPath() + (options.extension === undefined || options.extension === null ? '' : '.' + options.extension.replace(/^\./, ''));
 };
 
 module.exports.directory = () => {

test.js

@@ -5,10 +5,29 @@ import tempy from '.';
 
 test('.file()', t => {
 	t.true(tempy.file().includes(tmpdir()));
+	t.false(tempy.file().endsWith('.'));
+	t.false(tempy.file({extension: undefined}).endsWith('.'));
+	t.false(tempy.file({extension: null}).endsWith('.'));
 	t.true(tempy.file({extension: 'png'}).endsWith('.png'));
 	t.true(tempy.file({extension: '.png'}).endsWith('.png'));
 	t.false(tempy.file({extension: '.png'}).endsWith('..png'));
 	t.true(tempy.file({name: 'custom-name.md'}).endsWith('custom-name.md'));
+
+	t.throws(() => {
+		tempy.file({name: 'custom-name.md', extension: '.ext'});
+	});
+
+	t.throws(() => {
+		tempy.file({name: 'custom-name.md', extension: ''});
+	});
+
+	t.notThrows(() => {
+		tempy.file({name: 'custom-name.md', extension: undefined});
+	});
+
+	t.notThrows(() => {
+		tempy.file({name: 'custom-name.md', extension: null});
+	});
 });
 
 test('.directory()', t => {