Initialize postman variables using Pre-request script

 Often times we need to set postman variables before call API and API requests may use other API responses. Postman offers a pre-request script section that can be used to initialize postman variables.

In the below request, I require to send a mfa-token as part of the header to consume API, but mfa-token is not a static one to hardcode in postman global variables. I had get this for each request to get updated mfa-token from other API. This can be achieved through pre-request script to set dynamic values.

Set mfa-token variable through pre-request script by consuming another API response - 

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const reqObject = {

  url: 'http://internalUrl/authentication/mfa-token',

  method: 'GET',

  header: {'channel':'customer'}

};

pm.sendRequest(reqObject, (err, res) => {

    token = res.json()

    console.log(`fetched token ${token.tokenValue}`)

    pm.environment.set("mfa-token", token.tokenValue);

});