匹配单词的正则表达式

Question

I want to get the variable names in javascript which define a string for that I have wrote a regular expression

var x = "sdfsfsdf";

((\w.*?)(\s*=\s*)(['"]*)(.+?)(['"]*)\1)

The problem with this expression is when I am using RegExp.$2 I should get the variable name as x as we consider the above code. It works fine with some expression but if there is code like

function(a) {var b = document.createElement("script");}

then the result is function(a){var b .

Please help me change my regular expression so it works in both cases.

NOTE: javascript variables can also be declared without var ie x = "sdfsfsf";

Answer 1

If your strings won't be too crazy, you can try this:

/[a-z_$][a-z0-9$_]*\s*=\s*.*?(;|$)/gi

Tests:

> var r = /[a-z_$][a-z0-9$_]*\s*=\s*.*?(;|$)/gi;
  undefined
> 'var x = "sdfsfsdf";'.match(r);
  ["x = "sdfsfsdf";"]
> 'function(a) {var b = document.createElement("script");}'.match(r);
  ["b = document.createElement("script");"]

Answer 2

/(^|;|{)\s*(var\s+)?(\S+)\s*=\s*['"][^'"]*['"]\s*(}|;|$)/i

(^|;|{)          at the beginning, after a semicolon or the bracket
\s*              0-n whitespace characters
(var\s+)?        could be followed by "var" with at least one whitespace
(\S+)            at least one none whitespace character
\s*=\s*          equal sign with possibly surrounded whitespaces
['"][^'"]*['"]   a 'string'
\s*(}|;|$)       have to end with the bracket or a semicolon or the end of the variable has been reached

Also see this example .

Answer 3

Try this regex: ([^\w]?(\w.*?)(\s*=\s*)(['"]*)(.+?)(['"]*)\1)