Strings
A string literal can be wrapped in single quotes or double quotes. It can contain
zero or more characters. The \
(backslash) is the
escape character. JavaScript was built at a time when Unicode was a 16-bit character
set, so all characters in JavaScript are 16 bits wide.
JavaScript does not have a character type. To represent a character, make a string with just one character in it.
The escape sequences allow for inserting characters into strings that are not
normally permitted, such as backslashes, quotes, and control characters. The
\u
convention allows for specifying character
code points numerically.
"A" === "\u0041"
Strings have a length
property. For example,
"seven".length
is 5.
Strings are immutable. Once it is made, a string can never be changed. But it is
easy to make a new string by concatenating other strings together with the +
operator. Two strings containing exactly the same
characters in the same order are considered to be the same string. So:
'c' + 'a' + 't' === 'cat'
is true.
Strings have methods (see Chapter 8):
'cat'.toUpperCase( ) === 'CAT'
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