I want to check my URL that has exactly a **specific** format.
I have this URL

```
www.example.com?rt=12365

```

I want to check if income URL has below format

```
?rt= number

```

then do something.
I use the router like my below code:

```
const queryParams = router.url

```

but I don't know **how** to check it. I'm new to typescript and angular, please help me