htmlpretty

README

htmlpretty

The codeberg.org/derat/htmlpretty Go package pretty-prints an already-parsed HTML5 document, adding and removing whitespace to make it easier for humans to read. <script> and <style> tags and attribute values are (hopefully) left untouched.

The significance of whitespace in HTML is a very complicated topic, e.g.

• https://developer.mozilla.org/en-US/docs/Web/API/Document_Object_Model/Whitespace
• https://medium.com/@patrickbrosset/when-does-white-space-matter-in-html-b90e8a7cdd33

This package's handling of it is rudimentary, and I'm certain that I've gotten things wrong in places. As a trivial example, some lines may end up with an unnecessary trailing space.

There are a few existing Go packages that appear to provide similar functionality. I haven't tried them since I figured I'd run into edge cases and I wanted to understand the code well so I can tweak it as needed, but they're probably worth checking out.

Usage

import (
	"golang.org/x/net/html"
	"codeberg.org/derat/htmlpretty"
)
// ...
	node, err := html.Parse(r)
	if err != nil {
		// ...
	}
	if err := htmlpretty.Print(w, node, "  " /* indent */, 120 /* wrap */); err != nil {
		// ...
	}

A trivial command-line program named htmlpretty that reads a document from stdin and writes it to stdout is also provided:

% go install codeberg.org/derat/htmlpretty/cmd/htmlpretty
% htmlpretty -indent='    ' -wrap=80 <old.html >new.html

Documentation

Overview

Package htmlpretty pretty-prints HTML5 documents.

Index

• func Print(w io.Writer, root *html.Node, indent string, wrap int) error

Functions

func Print

func Print(w io.Writer, root *html.Node, indent string, wrap int) error

Print pretty-prints the supplied HTML document to w. The supplied indent string is used for a single level of indenting. If wrap is positive, lines will be wrapped at that many bytes where possible.