Feature: pre-parse string of arguments to argv

[juergba]

Description

closes #180

Pre-parse a string of arguments into argv, as Node launched in Bash builds process.argv.slice(2).
Incl. the handling of quoting and escaped metacharacters.

We add a new method toArgv()to Parser.

'use strict';
const parser = require('yargs-parser');

let argv = parser.toArgv(String.raw`--foo "bar hello" "testing \" this"`);
console.log(argv);       // [ '--foo', 'bar hello', 'testing " this' ]

let args = parser(argv, {
        array: ['foo']
});
console.log(args);       // { _: [], foo: [ 'bar hello', 'testing " this' ] }

Running Node on Bash and calling parser.toArgv should result in an identical argv:

$ node test.js --foo "bar hello" "testing \" this"
// process.argv.slice(2) === [ '--foo', 'bar hello', 'testing " this' ]

// let res = parser.toArgv(`--foo "bar hello" "testing \\" this"`)  // ok, works
let res = parser.toArgv(String.raw`--foo "bar hello" "testing \" this"`)
// res === [ '--foo', 'bar hello', 'testing " this' ]

[bcoe]

🎉 thanks for taking this on @juergba, @cdhowie do you think this would work for your use-case.

[bcoe]

@juergba coming back to this, I would personally rather we just document arrgv in the README, with a clear example of how one would use this to parse a complex argument string, rather than introducing an additional dependency to the chain.

At the end of the day, someone just invokes aargv, might as well just point folks towards that dependency?

[juergba]

@bcoe yes, I can live with your decision.

I leave the README update to someone else though, I don't have time for this right now.
So I'm closing this PR.

[bcoe]

@juergba 👌 appreciate the work you put into this.