fix: check for name of HotModuleReplacementPlugin to avoid RangeError

[jdb8]

• This is a bugfix
• This is a feature
• This is a code refactor
• This is a test update
• This is a docs update
• This is a metadata update

For Bugs and Features; did you add new tests?

Yes

Motivation / Use-Case

Fixes #87, a long-standing subtle bug which seems to have tripped up a lot of people historically.

Breaking Changes

No breaking changes.

Additional Info

See my comment on the issue: #87 (comment). The only way I can see this solution being a problem is if we're worried about configs that are using --hot and also have a plugin that isn't HotModuleReplacementPlugin but has the same name. In that case, we'd no longer inject the real HMR plugin. I'm not sure how likely this is and I seem to remember seeing other webpack plugins that check the name string rather than relying on the constructor reference (probably for this same reason).

However, if we are concerned and if there's a property we can additionally check on the instances of the plugin, that would potentially be more robust. Ideally it'd be a property that's existing on the HotModuleReplacementPlugin for a while to make it as backward-compatible as possible.

[codecov]

Codecov Report

Merging #2146 into master will not change coverage.
The diff coverage is 100%.

@@           Coverage Diff           @@
##           master    #2146   +/-   ##
=======================================
  Coverage   92.56%   92.56%           
=======================================
  Files          33       33           
  Lines        1265     1265           
  Branches      361      361           
=======================================
  Hits         1171     1171           
  Misses         87       87           
  Partials        7        7

Impacted Files	Coverage Δ
lib/utils/addEntries.js	100% <100%> (ø)	⬆️

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update f6653e7...8537ad6. Read the comment docs.

[alexander-akait]

Good job, thanks!