Fix check for webpack/hot/log when setting HMR log level

[lbogdan]

What kind of change does this PR introduce?
Bugfix.

Did you add or update the examples/?
Not needed.

Summary
Some time ago I authored PR #926. Which, strangely enough, caused issue #1049.

The original code was

  var hotCtx = require.context("webpack/hot", false, /^\.\/log$/);
  if(hotCtx.keys().length > 0) {
    hotCtx("./log").setLogLevel(level);
  }

Somehow I was under the impression that hotCtx.keys() can only return [] or ["./log"], and with this assumption, the check hotCtx.keys().length > 0 is correct. For some strange reason, as per issue #1049, it returned ["../package.json", "./console", "./formatters"], which doesn't match the regex at all, so I don't really know what happened there. In this case, of course, the check becomes wrong.

Now, this is the fix for #1049 in PR #1050

  if(hotCtx.keys().length > 0) {
    var contextKeys = hotCtx.keys();
    if(contextKeys.length && contextKeys["./log"]) {
      ...

which doesn't work, because contextKeys is an array, so contextKeys["./log"] will always be false.

So the correct check would be if (hotCtx.keys().indexOf('./log') !== -1) { ....

Does this PR introduce a breaking change?
No.

[lbogdan]

Cc @johan-lejdung.

[johan-lejdung]

Ah damn, of course it's an array.. Don't know what I was thinking :) If I could, I would approve this change!

The build seems to fail, but not related to this file. There seem to be a linting error in Server.js:

/home/travis/build/webpack/webpack-dev-server/lib/Server.js
  142:17  error  Strings must use singlequote  quotes
✖ 1 problem (1 error, 0 warnings)
  1 error, 0 warnings potentially fixable with the `--fix` option.

[lbogdan]

What's even stranger is that it fails only on node 6 and 4, 8 is ok. 😄

[johan-lejdung]

Quickly looked through the changelog for node 8 and there were a lot of Array changes, maybe they allow such access now.

[lbogdan]

That's an eslint error, so I don't see any reason why it would work differently in node 8 vs. node 4 or 6. Anyway, fixed it in #1098.

[codecov]

Codecov Report

Merging #1096 into master will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##           master    #1096   +/-   ##
=======================================
  Coverage   71.92%   71.92%           
=======================================
  Files           5        5           
  Lines         463      463           
  Branches      148      148           
=======================================
  Hits          333      333           
  Misses        130      130

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[lbogdan]

Any news on this?

[shellscape]

@lbogdan you're a rock star for getting these fixes in. very much appreciated! but I beg of you some additional patience please 😄 we're all human on this side, and to say the last two weeks have been personally trying would be an understatement. please note that it may take a week or so to get a patch release out. I'll be out of town and I don't like to release unless I'm around to put out any fires that pop up.

[lbogdan]

@shellscape Thank you for your kind words, they might not necessarily reflect the reality! 😄
That was just a follow up, sorry if I came off as impatient, I was just curious about an update. I know OSS is made out of people's personal time, and I really appreciate these people and their hard work!