I have a library in JS at this path in a module.

magento2\app\code\vendor_name\module_name\view\frontend\web\script.js

And it is initialised to the header with the following code:

checkout_index_index.xml

       <script src="Roman_hello::js/view/hello-init.js"/> 
</head>

And require-config.js file in vendor_name\module_name\view\frontend

with the following code:

var config = {
    map: {
        '*': {
            lazyloadScript:'vendorname_modelname::library/dist/libscript.min.js'
        }
    }
};

And on click i call the initialised library to the default.js at this path.

vendor_name\module_name\view\frontend\web\js\view\payment\default.js

but as always this gives error default.js:31 Uncaught (in promise) ReferenceError: default_var is not defined at default.js:31

what thing am I missing?