LazyHTML.Tree (LazyHTML v0.1.14)

This module deals with HTML documents represented as an Elixir tree data structure.

Validity

Trees returned by LazyHTML.to_tree/2 are always valid. If you build or change a tree yourself, you must make sure it is valid, that is, it could be produced by parsing HTML. The tree is not validated when serialized. For example, tag and attribute names must not contain whitespace, / or >, comments must not contain -->, and text in <script> or <style> must not contain its own end tag. Otherwise, the serialized HTML may be parsed into a different tree.

Summary

Types

html_attribute()

html_comment()

html_node()

html_tag()

html_text()

t()

Functions

postreduce(tree, acc, fun)

Performs a depth-first, post-order traversal of the given tree.

postwalk(tree, fun)

Same a postwalk/3, but with no accumulator.

postwalk(tree, acc, fun)

Performs a depth-first, post-order traversal of the given tree.

prereduce(tree, acc, fun)

Performs a depth-first, pre-order traversal of the given tree.

to_html(tree, opts \\ [])

Serializes Elixir tree data structure as an HTML string.

Types

html_attribute()

@type html_attribute() :: {String.t(), String.t()}

html_comment()

@type html_comment() :: {:comment, String.t()}

html_node()

@type html_node() :: html_tag() | html_text() | html_comment()

html_tag()

@type html_tag() :: {String.t(), [html_attribute()], [html_node()]}

html_text()

@type html_text() :: String.t()

t()

@type t() :: [html_node()]

Functions

postreduce(tree, acc, fun)

@spec postreduce(
  t(),
  acc,
  (html_node(), acc -> acc)
) :: acc
when acc: term()

Performs a depth-first, post-order traversal of the given tree.

This function traverses the tree without modifying it, check postwalk/2 and postwalk/3 if you need to modify the tree.

postwalk(tree, fun)

@spec postwalk(t(), (html_node() -> html_node() | [html_node()])) :: t()

Same a postwalk/3, but with no accumulator.

postwalk(tree, acc, fun)

@spec postwalk(
  t(),
  acc,
  (html_node(), acc -> {html_node() | [html_node()], acc})
) :: {t(), acc}
when acc: term()

Performs a depth-first, post-order traversal of the given tree.

The mapper fun can return a list of nodes to replace the given node. In order to remove a node, return an empty list.

prereduce(tree, acc, fun)

@spec prereduce(
  t(),
  acc,
  (html_node(), acc -> acc)
) :: acc
when acc: term()

Performs a depth-first, pre-order traversal of the given tree.

This function traverses the tree without modifying it, check postwalk/2 and postwalk/3 if you need to modify the tree.

to_html(tree, opts \\ [])

@spec to_html(
  t(),
  keyword()
) :: String.t()

Serializes Elixir tree data structure as an HTML string.

Options

:skip_whitespace_nodes - when true, ignores text nodes that consist entirely of whitespace, usually whitespace between tags. Defaults to false.

Examples

iex> tree = [
...>   {"html", [], [{"head", [], [{"title", [], ["Page"]}]}, {"body", [], ["Hello world"]}]}
...> ]
iex> LazyHTML.Tree.to_html(tree)
"<html><head><title>Page</title></head><body>Hello world</body></html>"

iex> tree = [
...>   {"div", [], []},
...>   {:comment, " Link "},
...>   {"a", [{"href", "https://elixir-lang.org"}], ["Elixir"]}
...> ]
iex> LazyHTML.Tree.to_html(tree)
~S|<div></div><!-- Link --><a href="https://elixir-lang.org">Elixir</a>|

iex> tree = [
...>   {"p", [],
...>    [
...>      "\n  ",
...>      {"span", [], [" Hello "]},
...>      "\n  ",
...>      {"span", [], [" world "]},
...>      "\n"
...>    ]},
...>   "\n"
...> ]
iex> LazyHTML.Tree.to_html(tree, skip_whitespace_nodes: true)
"<p><span> Hello </span><span> world </span></p>"