I'm watching ECMA-262 (JavaScript 5 edition) and cannot understand what is "code unit value"?
Can anyone tell me?
Thank you very much!
2
- Can you add some context, like the paragraph it is mentioned in?Pekka– Pekka2011-03-09 10:50:16 +00:00Commented Mar 9, 2011 at 10:50
- Pekka, thank you for your reply! The question has been answered by Mathias Bynens at below. :)weilou– weilou2011-03-09 12:35:44 +00:00Commented Mar 9, 2011 at 12:35
Add a comment |
1 Answer
A JavaScript string is a sequence of unsigned 16-bit integers, also known as code units.
A code point is how the Unicode standard represents symbols and non-symbols. Code points are represented as a four-to-six digit hexadecimal number, typically prefixed with U+, e.g. U+0061 LATIN SMALL LETTER A.
The difference is that what can be part of a code unit depends on the character encoding that is used. A code point however, is merely the concept of a “character” that can then potentially be encoded using UTF-8, for example.
For more information, read chapter 2 of the Unicode spec, especially 2.4 Code points and characters.
1 Comment
brainkim
I don’t think this is correct. ecma-international.org/ecma-262/5.1/#sec-6 defines the terms "code unit" and "code point" as two separate concepts, the former being limited to characters which can be represented by 16 bits and the latter referring to a Unicode scalar value.