Handle template starting with empty line

index.test.ts

@@ -20,6 +20,20 @@ test('It reindent placeholders', () => {
     `).toBe('<test>\n    test\n    value\n</test>');
 });
 
+test('It correctly detect indentation when first line is empty', () => {
+    expect(indent`
+
+        Test
+    `).toBe('\nTest');
+});
+
+test('It correctly detect indentation when last line is empty', () => {
+    expect(indent`
+        Test
+
+    `).toBe('Test\n');
+});
+
 test('Nested indent test', () => {
     const list = ['First', 'Second'];
 

index.ts

@@ -12,7 +12,7 @@ const indentTag = (strings: TemplateStringsArray, ... expressions: any[]) => {
     parts[strings.length - 1] = parts[parts.length - 1].replace(/\n[ \t]*$/, '');
 
     // Dedent using indent from first part
-    const indent = parts[0].match(/^[ \t]*/)![0];
+    const indent = parts[0].match(/^\n*([ \t]*)/)![1];
 
     const deindent = new RegExp(`(^|\n)${indent}`, 'g');