Pre request script in postman | Explained in best possible way 2020 |

Pre request script in postman explained in the best possible way, you will not be having any doubts after that. Examples that we have discussed in this video is are as follows
1. When one request is dependent on another request. Ex: Bearer token required for running a request each time.
2. writing pre-request script at collection level.
3. Writing pre request script when you want to process something before the request.

Writing pre-request scripts
You can use pre-request scripts in Postman to execute JavaScript before a request runs. By including code in the Pre-request Script tab for a request, collection, or folder, you can carry out pre-processing such as setting variable values, parameters, headers, and body data. You can also use pre-request scripts for debugging code, for example by logging output to the console.

An example usage of pre-request scripting could be as follows:

You have a series of requests in a collection and are running them in a sequence, e.g. using the collection runner.
The second request is dependent on a value returned from the first request.
The value needs to be processed before you pass it to the second request.
The first request sets the data value from a response field to a variable in its Tests script.
The second request retrieves the value and processes it in its Pre-request Script, then sets the processed value to a variable (which is referenced in the second request, e.g. in its parameters).

You can add pre-request scripts to entire collections as well as to folders within collections. In both cases, your pre-request script will run before every request in the collection or folder. This allows you to define commonly used pre-processing or debugging steps you need to execute for multiple requests.

To add pre-processing to a group of requests, locate the collection or folder in Collections on the left of Postman. Click ... to View more actions and select Edit.
Open Pre-request Scripts to enter code that will run before every request in the collection or folder.

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[anjalibohra]

Where can I get the piece of code u have pasted in pre requisite?

[shubhadapatil]

Hi if we have one variable which needs to be updated for each test case, how can we write in prerequest code

[thiyagarajananguraj]

Thanks for that, it really worked for me to automate my api

[soniamiglani]

HI Sir, thank you!! Can you explain how to refer pre-request script in different collection?

[AshwathVellurNagaraju]

How to add the params details in the prerequisites script?

[Pingsmingu]

can you please show how to skip a request via prescript