Need help to understand the javascript function from vbcookbook

Summary:

Hi Experts

I want help to understand below javascript function which is used in Buffering data provider vbcookbook.

Here I'm unable to understand what is "value" i dont see any value being passed as an argument for this javascript fucntion but it is using within the code in if condition. What does value will hold ? its not assigned any value. Please help

    salaryInRangeValidator(record, disableRowEditExit) {

      return {

        getHint: () => "Salary has to be in job salary range",

        validate: (value) => {

          let jobRecord = record.jobObject.items[0];

          if (jobRecord.minSalary === undefined) {

            throw new Error(

              "cannot validate because range is not available yet"

            );

          } else if (