Enhancing website functionality with Regex in Javascript

Question

Enhancing website functionality with Regex in Javascript

So, here is the code I am working with:

var patt = new RegExp("/.+/g");
var device_id = patt.exec("javascript:project_id:256, device_id:2232");

Surprisingly, after running the above code, the value of device_id is empty and I can't seem to figure out why.

My actual goal is to extract the device id (2232), but I used the above pattern for testing because I thought it would return everything. Here is the regex I tried using for the device id:

/device_id:([0-9]+)/

I also attempted using javascript.match function, but unfortunately that didn't solve the issue either.

javascript regex

Answer 1

Answer №1

When using double quotes as the regex delimiters in the RegExp constructor, there is no need to include the forward slash delimiter within the double quotes. Additionally, modifiers such as g (global modifier) should be specified as a separate parameter.

> var patt = new RegExp("device_id:([0-9]+)", "g");
undefined
> patt.exec("javascript:project_id:256, device_id:2232")[1]
'2232'

OR

> var patt = /device_id:([0-9]+)/g;
undefined
> patt.exec("javascript:project_id:256, device_id:2232")[1]
'2232'

Answer 2

When using double quotes as the regex delimiters in the RegExp constructor, there is no need to include the forward slash delimiter within the double quotes. Additionally, modifiers such as g (global modifier) should be specified as a separate parameter.

> var patt = new RegExp("device_id:([0-9]+)", "g");
undefined
> patt.exec("javascript:project_id:256, device_id:2232")[1]
'2232'

OR

> var patt = /device_id:([0-9]+)/g;
undefined
> patt.exec("javascript:project_id:256, device_id:2232")[1]
'2232'

Answer 3

Answer №2

Consider initializing your regular expression like this:

let pattern = new RegExp(".+");

or

let pattern = /.+/g;

Answer 4

Consider initializing your regular expression like this:

let pattern = new RegExp(".+");

or

let pattern = /.+/g;

Enhancing website functionality with Regex in Javascript

Answer №1

Answer №2

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