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.

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