Question

I need to check if a string starts with the following: “+=”

I’ve tried

str.search("+="));

and

str.search("\+\="));

but get

Uncaught SyntaxError: Invalid regular
expression: /+=/: Nothing to repeat

Can you help me with this, and also recommend a good resource for JavaScript regular expressions?

Answer 1

Try this regex:

/^\+=/.test(str);

It will return true if the string starts with +=. The ^ (caret) says “match from the beginning of the string”. The + needs to be escaped because it is a regex metacharacter that means “one or more of the preceding” (and that’s not what we want).