Collection variables not set after executing collections pre-request-script without errors

🙋 Help
,
1

My question:
i have been trying to use functions in my collections pre-request script to create variables.
when i check for the variable inside the collections pre-request script its found,
howerver when i do the same afterwards its gone. i couldnt find it manually either.
i am quite new to postman, am i missing something here?

Details:
this is the script where i call the function from the collections pr script:

Screenshot_20221103_135354
Screenshot_20221103_135354708×123 7.97 KB

this is the pre-request script of the collection where i create the new variable:

Screenshot_20221103_134703
Screenshot_20221103_134703705×309 6.84 KB

this is the console output:
image

I’ve already tried:
i tried using global or enviornment varibles instead, but that did nothing.

what should i be doing differently?
im using version 10.0.1

3

Hi @pherrmann18

The issue here is that the pm.collectionVariables.get

pre-request script of the collection by default executes before every call within that collection. So I’m struggling to see why you would need to encase this in a function and call that function within the test script… (it would have already executed the collection pre-req by the time the test script runs).

If you remove the function and just run the code inside it works as you described…

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You can also see that the variable get added and updated too;

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4

hey @w4dd325 ,
my goal was to create a set of functions i could then use globally in that collection.
i dont want it to execute everything before every request.
this was more of an example.
is there some way to achieve that?

6

If you want to call a function from a pre-request script, consider the following (very basic) example using global variables. Might be an option.

Pre-request script.

postman.setGlobalVariable("functionA", () => {
    console.log("hello world")
});

Tests tab

Hello = eval(pm.globals.get("functionA"));
Hello();
7

@pherrmann18

This also works.

Pre-request script (can be set at the request or collection level).

Object.prototype.log = (msg) => {
    console.info(pm.info.requestName + " | " + msg);
};

Tests tab

pm.log("this is my log message");

To extend this.

The following will allow you to set a collectionVariable.

Pre-request script

Object.prototype.myGlobalFunction = function(myPm, key, value){
     myPm.collectionVariables.set(key, value);
}

Tests tab

_.myGlobalFunction(pm, "myKey", "myValue");

It does seem that Object.prototype can work.

Back to your original request.

Pre-request script.

Object.prototype.createObject = function(myPm){

    var counter = myPm.collectionVariables.get("obj_counter");
    myPm.collectionVariables.set(`obj_save_nb_${counter}`, `Hello there ${counter}`);
    counter++;
    myPm.collectionVariables.set("obj_counter", counter);     

}

Tests tab. (Counter set to 0 and using a loop)

pm.collectionVariables.set("obj_counter", 0);

for (let i = 0; i < 10; i++) {
    _.createObject(pm);
    console.log(`obj_save_nb_${i}: ` + pm.collectionVariables.get(`obj_save_nb_${i}`));
}`

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