Not expanding unquoted variables correctly

Consider the following example:

$ export T="c d"
$ node -e 'console.log(JSON.stringify(process.env.T), process.argv)' a b $T

You get the following result:

"c d" [
  '/home/ec2-user/.nvm/versions/node/v17.0.1/bin/node',
  'a',
  'b',
  'c',
  'd'
]

The variable T is expanded in possitional args c and d. If we quote the variable then we get a different result:

$ export T="c d"
$ node -e 'console.log(JSON.stringify(process.env.T), process.argv)' a b "$T"
"c d" [
  '/home/ec2-user/.nvm/versions/node/v17.0.1/bin/node',
  'a',
  'b',
  'c d'
]

However, in the shell-quote library the situation is different. Consider the following example:

const shellQuote = require('shell-quote')

console.log(shellQuote.parse('test a b $T', { T: 'c d' }))

We get the following result:

[ 'test', 'a', 'b', 'c d' ]

Notice that the behaviour is different as in the variable T does not get expanded. In other words, the behaviour is similar to variable T beign quoted, i.e:

const shellQuote = require('shell-quote')

console.log(shellQuote.parse('test a b "$T"', { T: 'c d' })) // [ 'test', 'a', 'b', 'c d' ]

If shell-quote is used to parse string which are used to spown a process with environment variable that are not quoted, it will result in a completely different behaviour than the one expected from the standard shell.