Question

If I have a String in JavaScript

key=value

How do I make a RegEx that matches key excluding =?

In other words:

var regex = //Regular Expression goes here
regex.exec("key=value")[0]//Should be "key"

How do I make a RegEx that matches value excluding =?

I am using this code to define a language for the Prism syntax highlighter so I do not control the JavaScript code doing the Regular Expression matching nor can I use split.

Answer 1

Well, you could do this:

/^[^=]*/     // anything not containing = at the start of a line
/[^=]*$/     // anything not containing = at the end of a line

It might be better to look into Prism’s lookbehind property, and use something like this:

{
    'pattern': /(=).*$/,
    'lookbehind': true
}

According to the documentation this would cause the = character not to be part of the token this pattern matches.