[TIMOB-24610] Implement ability to transpile

[garymathews]

• Implement transpile option for jsanalyze()
• To supplement [TIMOB-24610] Support transpiling user JS code to ES5, or minimum target OS/JS engine support titanium-sdk#9512

EXAMPLE

...
const transpile = this.cli.tiapp.transpile || false;
const result = jsanalyze.analyzeJs(contents, {
	filename: from,
	minify: this.minifyJS,
	transpile: transpile,
	targets: {
		chrome: '62'
	}
});
...

• Can replace babel.transform for android and ios

JIRA Ticket

[sgtcoolguy]

May want to consider building up the JS object options for babel.transform so that when we transpire and minify we don't do it in two separate calls.

It's entirely possible that it may not matter, though. I'm just guessing it may have a performance impact.

Might want to try a quick test and see...

[sgtcoolguy]

I think this is supposed to be:

presets = [ [ env, { targets: opts.targets } ] ];

[sgtcoolguy]

I know this isn't specific to your changes, but I think we may want to consider some options to retain line numbers or generate debug source mappings.

If users choose to transpile and/or minify, the Studio debugger won't know how to map the original source to the generated files for setting breakpoint lines/etc.

I think we've always hacked around this in the past by basically turning off minify when debugging, but we're going to try and always transpile now (even though it may not result in any changes), so it'll be a bigger issue.

Unfortunately, I'm not sure if Babel has fixed their source mapping, as it turned out to be broken when I did the ES6 alloy changes: tidev/alloy#860

The ugly/simple fix is to set options.retainLines = true; which jumps through hoops to keep line numbers the same, but obviously may not really "minify" a file fully if it needs to keep a bunch of empty lines around.

[sgtcoolguy]

lib/jsanalyze.js#169 fix definitely needs to be done. Consider adding options.retainLines= true; for transpile.

[sgtcoolguy]

Merged manually. I forced retainLines = true for minify and/or transpile (not just minify).

[sgtcoolguy]

Manually merged.