需要使用输入参数获取正确的JavaScript语法

Question

I have js line like that agent.match(/(iphone|ipod|ipad)/) I need to make match parameters dynamic

So i tried to go like that agent.match('/(' + param + ')/') but it is not working. Whatever I put in param it is matching.

What I did wrong? And what / means?

Answer 1

When you are dynamically generate RegEx strings, its always better to use RegExp constructor. / is actually to tell JavaScript that you are going to use a Regular Expression literal. But when you put that inside quotes, it becomes a part of the string.

The simplest way to do this is to put them in a list like this

var data = ["iphone", "ipod", "ipad"];

And join them with | like this

agent.match(new RegExp("(" + data.join("|") + ")"))

This works because,

data.join("|")

will produce

iphone|ipod|ipad

We can concatenate ( and ) with that string to dynamically generate the pattern you wanted.