fix: add a not null check for the content property before throwing error

[sresant]

This check will fix #42 for webpack2 users.

[codecov]

Codecov Report

Merging #404 into master will decrease coverage by 0.03%.
The diff coverage is 100%.

@@            Coverage Diff             @@
##           master     #404      +/-   ##
==========================================
- Coverage   90.42%   90.38%   -0.04%     
==========================================
  Files           6        6              
  Lines         355      364       +9     
  Branches       74       77       +3     
==========================================
+ Hits          321      329       +8     
- Misses         34       35       +1

Impacted Files	Coverage Δ
index.js	91.03% <100%> (+0.2%)	⬆️
ExtractedModule.js	95.12% <0%> (-2.18%)	⬇️

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[bebraw]

Would it be possible to add a test against this case so we don't break it in the future? Good apart from that.

[sresant]

@bebraw Yea sure, it has been a busy couple weeks...I'll try getting some test this week.

[sresant]

@bebraw After looking at this a little further, any suggestions on testing this with watch mode running? I looked at the current set of test suites and it looks like they just run a single compilation using webpack. This test would require running watching mode.

[bebraw]

@sresant That's a good point. I would look into webpack core to see how it handles watch mode related tests.

If there's no way, let's merge. 👍

[sresant]

@bebraw Looking at it the webpack core version of the watchmode test suite is different from what this test would require to work so might be more difficult to implement :(

[bebraw]

@d3viant0ne Any thoughts on this? Small change.

[bebraw]

@michael-ciniawsky Maybe merge? I don't see this breaking anything so might as well. A comment would be good, though.

[michael-ciniawsky]

@sresant Please add a comment in case this causes regressions

[michael-ciniawsky]

@bebraw Yep it should be fine, but I'm not 💯 with ETWP yet tbh 😛

[michael-ciniawsky]

@sresant Thx

[michael-ciniawsky]

@sresant Please close and reopen the PR to trigger the CLA Bot again and sign the CLA :)

[nitruxa]

Took this change - build goes green, but in console every second build this error occurs:

Uncaught TypeError: Cannot read property 'call' of undefined
    at __webpack_require__ (bootstrap 278d682…:52)
    at Object.1145 (styles.css?7f97:4)
    at __webpack_require__ (bootstrap 278d682…:52)
    at Object.webpackJsonp.1098.module.exports.Object.defineProperty.value (bundle.js:1724)
    at __webpack_require__ (bundle.js:21)
    at Object.<anonymous> (bundle.js:130)
    at __webpack_require__ (bundle.js:21)
    at Object.webpackJsonp.1098.module.exports.Object.defineProperty.value (bundle.js:55)
    at __webpack_require__ (bundle.js:21)
    at webpackJsonp.1098.module.exports.Object.defineProperty.value (bundle.js:41)