add a Symbol polyfill

[seanparmelee]

• This is a bugfix
• This is a new feature
• This is a code refactor
• This is a test update
• This is a typo fix
• This is a metadata update

For Bugs and Features; did you add new tests?

No

Motivation / Use-Case

To maintain IE 10 & 11 compatibility, Symbol needs to be polyfilled since these browsers do not support it. Fixes #5.

Breaking Changes

None

Additional Info

This PR builds off the commit in your ie-assign-symbol branch; not sure if you wanted those changes regardless but if not I can remove them. With this PR, the loglevelnext.min.js file bumps up to 18 kB. I also gave useBuiltIns: 'usage' a shot and that bumped the size to 30 kB.

[codecov]

Codecov Report

Merging #6 into master will increase coverage by 0.08%.
The diff coverage is 100%.

@@            Coverage Diff             @@
##           master       #6      +/-   ##
==========================================
+ Coverage    93.7%   93.79%   +0.08%     
==========================================
  Files           4        4              
  Lines         143      145       +2     
  Branches       24       24              
==========================================
+ Hits          134      136       +2     
  Misses          9        9

Impacted Files	Coverage Δ
lib/MethodFactory.js	86.79% <100%> (ø)	⬆️
index.js	96.77% <100%> (+0.22%)	⬆️

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[seanparmelee]

this change was already in the branch. not sure if you prefer to keep it, but fwiw: https://jamie.build/last-2-versions

[seanparmelee]

The polyfill didn't place nicely with the Babel transformation code that results from the for..of so I changed this to a forEach. IE 11 was thowing an Object expected error.

[shellscape]

Thanks for putting that together. I'll take a look at it later tonight.

[MatTheCat]

Using this branch I no longer have an error regarding Symbol. There is another problem affecting IE and Edge but it seems to be fixed by webpack-contrib/webpack-hot-client#43

[shellscape]

Thanks for your work on this 🍺

In the future please keep from adding dist files and package-lock.