add: editorconfig

.editorconfig

@@ -0,0 +1,19 @@
+# EditorConfig: https://EditorConfig.org
+
+# top-most EditorConfig file
+root = true
+
+# Unix-style newlines with a newline ending every file
+[*]
+end_of_line = lf
+insert_final_newline = true
+
+# Matches multiple files with brace expansion notation
+# Set default charset
+[*.{js,ts}]
+charset = utf-8
+
+# Indentation override for all JS under lib directory
+[**.js]
+indent_style = space
+indent_size = 2