Autoindent

Autoindent is a feature in text editors and integrated development environments that automatically applies indentation when starting a new line, aligning with the indentation of the previous line or with language-specific rules. It aims to maintain consistent formatting and reduce manual typing, especially in code and structured text.

In practice, autoindent behaves in several ways. When you press Enter, the editor typically starts the new line at the same indentation level as the current line. Some modes also increase indentation after typing block-opening characters such as braces or keywords, and may decrease indentation when closing blocks. Many editors also apply indentation automatically when pasting multi-line text or reformatting code, and some adjust indentation using syntax-aware rules for the target programming language.

Editors differ in terminology and capabilities. Common options include plain autoindent, smart indent, cindent, and electric indent. Specific implementations appear in Vim, Emacs, Visual Studio Code, and JetBrains IDEs, each offering different degrees of language awareness and configurability. Users can usually enable or disable autoindent, choose tab width, and decide whether to insert spaces or actual tab characters. Language-specific formatting rules may override generic behavior via a formatter or language server.

Considerations include the potential for inconsistent styles across projects if editors are not configured uniformly. While autoindent can improve readability and speed, teams often rely on a shared formatter or style guide to ensure consistency across tools and environments.