It is easy to set GET parameters for HTTP request. You need to use the mustache brackets inside the URL itself.
The Flow Diagram

Steps To Set Get Parameters
1) Inject Node
– Payload – can set to anything. In my case I use timestamp

2) Function Node
– Set parameter GET value here
– In my case I use parameter name “path” and “limit”, set as msg.path and msg.limit
– You can use any name for your parameter name but it be the same as in HTTP Request Node

3) HTTP Request Node
– Choose method: GET
– In the URL, use mustache brackets to declare your variable {{{path}}}
– The parameter name must be same as in the Function Node

4) Debug Node
– Use to display the output

Notes:
Node Red version used – v0.20.7
Node Red Set Parameters HTTP Request GET – Flow File Example