feat: Support var as empty string

[yonecdeng]

use as

    {
        name: '#weblogger',
        var: '',
        path: ``,
    },

[eight04]

Could you elaborate? Why do you want to replace a variable with an empty string?

[yonecdeng]

Because there are iife packages that instead of providing a unique global variable, provide many variables mounted to the window. For example: https://cdnjs.cloudflare.com/ajax/libs/tslib/2.6.2/tslib.js

[yonecdeng]

source:

import {a,b} from 'tslib'
a()
b()

we need change it to:

a()
b()

instead of

tslib.a();
tslib.b();

[eight04]

I suggest mapping the import to window:

// config
externalGlobals({
  tslib: "window"
})

// source
import {a,b} from 'tslib'
a()
b()

// output
window.a();
window.b();

Replacing an identifier with an empty string may introduce syntax error or undefined variable error in other cases.