HtmlEscape class final

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 ' instead of ' since not all browsers understand '.
• / (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 & 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;