Reference Error

while generating new address:

var address = new Address.fromString(‘mwkXG8NnB2snbqWTcpNiK6qqGHm1LebHDc’);

I get an error:

ReferenceError: Address is not defined
at Object. (/home/predix/.npm-global/lib/node_modules/bitcore-node/lib/cli/kartiki.js:7:21)
at Module._compile (module.js:570:32)
at Object.Module._extensions…js (module.js:579:10)
at Module.load (module.js:487:32)
at tryModuleLoad (module.js:446:12)
at Function.Module._load (module.js:438:3)
at Module.runMain (module.js:604:10)
at run (bootstrap_node.js:394:7)
at startup (bootstrap_node.js:149:9)
at bootstrap_node.js:509:3

And also ,
while creating private key,

var privateKey = PrivateKey.fromWIF(‘cPBn5A4ikZvBTQ8D7NnvHZYCAxzDZ5Z2TSGW2LkyPiLxqYaJPBW4’);

I get such error::

ReferenceError: PrivateKey is not defined

Why is this so?Where I’m getting wrong or missing something?
Please help ,I’m new to all this stuff.

As the error says, Address and PrivateKey are not defined.
If you import bitcore-lib like this:
const bitcore = require('bitcore-lib')
than you should use

If you want to use PrivateKey directly you should define it at the beginning as:
const PrivateKey = require('bitcore-lib').PrivateKey

I strongly advise you to learn some Javascript basics before going on.