Implement build process to allow ES module support (ie. tree-shakable)

[mgdodge]

All existing functionality is preserved, all unit tests still pass. Even loaded in angularjs to verify umd wrapper correctly registers it when angular is present.

New features

• Rollup build process implemented - produces 3 builds: iife (minified for browser use), umd (for legacy apps, angularjs, commonjs, etc), and esm build (for modern bundlers, tree-shakeable!)

New files added outside of lib folder are for build process/npm support. Version numbers bumped to 1.5.0 in package.json/bower.json - when published to npm, these should be in sync. Retain copy of 1.4.4 in reference folder.

(This PR is a subset of changes from #137, focusing on just the build process. Remaining changes from that PR will be submitted separately.)

[mgdodge]

Any chance of this getting a response?

[rquadling]

Hi. Really sorry there's been no response. Unfortunately I cannot comment on the actual PR, but the principle here is good. I hope that others will be able to take a better look.

[sukima]

The produced output looks correct to me. What are the chances of getting this merged?

[Rycochet]

Needs someone with some time to look at it - the project needs a bit of updating regardless (ie, bower was deprecated ~5 years ago, should be in typescript, and there's another PR with some nice performance updates) - it's not large enough to be a major issue for most people so nobody really puts this high on their priorities for checking (the downside of a project that does its job well!)

[danieltroger]

This piece of code:

if (typeof define === 'function' && define.amd) {
  define(function () { return LZString; });
} else if( typeof module !== 'undefined' && module != null ) {
  module.exports = LZString
}

Just broke a customer website of ours (because it calls the define function). I assume it would have been fixed by this PR? Anyways, this would be awesome. We're considering either dropping lz-string or patching out that code now.

[Rycochet]

The new version uses vite and rollup to ensure there's both a real esmodule and commonjs build available!