HtmlEscape class Null safety

Converter which escapes characters with special meaning in HTML.

The converter finds characters that are significant in the HTML source and replaces them with corresponding HTML entities.

The characters that need escaping in HTML are:

  • & (ampersand) always needs to be escaped.
  • < (less than) and > (greater than) when inside an element.
  • " (quote) when inside a double-quoted attribute value.
  • ' (apostrophe) when inside a single-quoted attribute value. Apostrophe is escaped as &#39; instead of &apos; since not all browsers understand &apos;.
  • / (slash) is recommended to be escaped because it may be used to terminate an element in some HTML dialects.

Escaping > (greater than) isn't necessary, but the result is often found to be easier to read if greater-than is also escaped whenever less-than is.

Example:

const HtmlEscape htmlEscape = HtmlEscape();
String unescaped = 'Text & subject';
String escaped = htmlEscape.convert(unescaped);
print(escaped); // Text &amp; subject

unescaped = '10 > 1 and 1 < 10';
escaped = htmlEscape.convert(unescaped);
print(escaped); // 10 &gt; 1 and 1 &lt; 10

unescaped = "Single-quoted: 'text'";
escaped = htmlEscape.convert(unescaped);
print(escaped); // Single-quoted: &#39;text&#39;

unescaped = 'Double-quoted: "text"';
escaped = htmlEscape.convert(unescaped);
print(escaped); // Double-quoted: &quot;text&quot;

unescaped = 'Path: /system/';
escaped = htmlEscape.convert(unescaped);
print(escaped); // Path: &#47;system&#47;
Inheritance

Constructors

HtmlEscape([HtmlEscapeMode mode = HtmlEscapeMode.unknown])
Create converter that escapes HTML characters.
const

Properties

hashCode int
The hash code for this object.
read-only, inherited
mode HtmlEscapeMode
The HtmlEscapeMode used by the converter.
final
runtimeType Type
A representation of the runtime type of the object.
read-only, inherited

Methods

bind(Stream<String> stream) Stream<String>
Transforms the provided stream.
inherited
cast<RS, RT>() Converter<RS, RT>
Provides a Converter<RS, RT> view of this stream transformer.
inherited
convert(String text) String
Converts input and returns the result of the conversion.
override
fuse<TT>(Converter<String, TT> other) Converter<String, TT>
Fuses this with other.
inherited
noSuchMethod(Invocation invocation) → dynamic
Invoked when a non-existent method or property is accessed.
inherited
startChunkedConversion(Sink<String> sink) StringConversionSink
Starts a chunked conversion.
override
toString() String
A string representation of this object.
inherited

Operators

operator ==(Object other) bool
The equality operator.
inherited