In the Internet Object format, whitespace refers to any character with a Unicode code point less than or equal to U+0020 (i.e., characters in the range U+0000 to U+0020). This range includes both non-printable control characters and common whitespace characters such as the horizontal tab (U+0009), newline (U+000A), vertical tab (U+000B), form feed (U+000C), carriage return (U+000D), and space (U+0020).
In addition to the characters in the range U+0000 to U+0020, the Internet Object format also includes characters in the Unicode whitespace category as whitespace. This includes characters such as the non-breaking space (U+00A0), em space (U+2003), and en space (U+2002), among others. Including Unicode whitespace characters can also make it easier to work with text in languages that use non-Latin scripts, such as Arabic, Chinese, or Japanese.
It's also worth noting that the Internet Object format recognizes the zero-width non-breaking space (U+FEFF) as whitespace. This character is often used as a byte order mark (BOM) in Unicode-encoded documents. Incorporating a more comprehensive range of whitespace characters in Internet Object offers several advantages that can make the format easier to work with, more readable, and more compatible with different systems and programming languages.
The following table shows a list of valid whitespace characters.
code points
U+0000 to U+0020
Space, Line Feed, Carriage Return, Tab, Bell, etc.
Any character having charCode <=0x20 such as space. ASCII space and control characters
Ogham Space Mark
Space used in Ogham scripts
En Quad
Space equal to the width of the lowercase letter "n"
Em Quad
Space equal to the width of the uppercase letter "M"
En Space
Space equal to half the width of the em space
Em Space
Space equal to the width of the em space
Three-per-Em Space
Space equal to one-third of an em space
Four-per-Em Space
Space equal to one-quarter of an em space
Six-per-Em Space
Space equal to one-sixth of an em space
Figure Space
Space equal to the width of a numeral character
Punctuation Space
Space used for punctuation
Thin Space
Space narrower than the regular space character
Hair Space
Very narrow space used for special purposes
Line Separator
Character used to separate lines in text
Paragraph Separator
Character used to separate paragraphs in text
Narrow No-Break Space
Non-breaking space narrower than the regular space character
Medium Mathematical Space
Space used in mathematical notation
Ideographic Space
Space used in East Asian scripts
Byte Order Mark (BOM)
Zero Width Non-Breaking Space
Internet Object is not whitespace-sensitive, which means that the parser ignores the whitespaces surrounding the values and structural elements. However, any whitespace characters found within the values or strings themselves are preserved.
Using whitespace can help to make the Internet Object document more readable, but it is not required. When transmitting data over the wire, any whitespace characters can be safely ignored as they do not affect the document's content.