string

Links

On Unicode
- JavaScript uses UCS-2 encoding internally
- octal escape sequence
  - Note that there’s one exception here: by itself, \0 is not an octal escape sequence. It looks like one, and it’s even equal to \00 and \000, both of which are octal escape sequences — but unless it’s followed by a decimal digit, it acts like a single character escape sequence. Or, in spec lingo:EscapeSequence :: 0 [lookahead ∉ DecimalDigit]. It’s probably easiest to define octal escape syntax using the following regular expression: \\(?:[1-7][0-7]{0,2}|[0-7]{2,3}).
  - Octal escapes have been deprecated in ES5
  - They produce syntax errors in strict mode
- hexadecimal escapes
- Unicode escapes
  - You could define Unicode escape syntax using the following regular expression: \\u[a-fA-F0-9]{4}.
- ECMAScript 6: Unicode code point escapes
- Characters without special meaning can be escaped as well (e.g. '\a' == 'a'), but this is of course not needed. However, using \u outside of a Unicode escape sequence, or \x outside of a hexadecimal escape is disallowed by the specification, and causes some engines to throw a syntax error.
- \v and \0 escapes are not allowed in JSON strings.
String
Number and String
tag: String
Properties
Static methods of String
- fromCharCode
Methods
StringView - based on typed arrays
Character Access
- charAt(i) is much more widely supported than indexing / [i]
localeCompare (compatibility)
- Checking for support for locales and options arguments
String primitives vs. instances
String() → a safer toString()
- Handles null and undefined safely.
article: JavaScript has a Unicode problem

Methods

Method	Description
`indexOf(searchValue[, fromIndex])`	Returns `-1` if the value is not found.
`split([separator][, limit])`]	`separator` can be a string or a regex. If omitted, you get a array of one element containing the string.
`substr(start[, length])`	`start` can be negative and is equivalent to `string.length + start`. If `abs(start) > string.length` or `length` is less than 1, you get an empty string.
`substring(indexA[, indexB])`	`indexA` is inclusive and `indexB` is exclusive. If either is negative, they are treated as zero and if either is greater than the string length, they're set equal to the string length.

Gotchas

Ref: String primitives vs. instances

var s_prim = "foo";
var s_obj = new String(s_prim);

console.log(typeof s_prim); // "string"
console.log(typeof s_obj);  // "object"

console.log("===:", s_prim === s_obj); // false
console.log("=== + valueOf:", s_prim === s_obj.valueOf()); // true

Snippets

// gist
function isString(obj) {
  return Object.prototype.toString.call(obj) == '[object String]';
};

// capture global on init
var isString = (function() {
    var _toString = Object.prototype.toString;
    return function isString(obj) {
      return _toString.call(obj) == '[object String]';
    };
  })();