Question

I am having trouble googling this. In some code I see

name = name.replace(/[\[]/,"\\\[").replace(/[\]]/,"\\\]");

/[\[]/ looks to be 1 parameter. What do the symbols do? It looks like it’s replacing [] with \[\] but what specifically does /[\[]/ do?

Answer 1

The syntax /…/ is the literal regular expression syntax. And the regular expression [\[] describes a character class ([…]) that’s only character the [ is). So /[\[]/ is a regular expression that describes a single [.

But since the global flag is not set (so only the first match will be replaced), the whole thing could be replaced with this (probably easier to read):

name.replace("[", "\\[").replace("]","\\]")

But if all matches should be replaced, I would probably use this:

name.replace(/([[\]])/g, "\\$1")