gistfile1.js

function myFn1 (arg1) {
    var var1 = doSomethingWith(arg1), // set breakpoint here
        var2 = doSomethingElseWith(var1);
    
    _.each([1, 2, 3], function (val) {
        doAnotherThingWth(var2); // var2 is still available in dev tools here, but var1 is not
    })
};