Istanbul: Error running `istanbul check-coverage`

[domharrington]

/project-path/node_modules/istanbul/lib/object-utils.js:247
            for (i = 0; i < retArray.length; i += 1) {
                                    ^

TypeError: Cannot read property 'length' of undefined
    at /project-path/node_modules/istanbul/lib/object-utils.js:247:37
    at Array.forEach (native)
    at Object.mergeFileCoverage (/project-path/node_modules/istanbul/lib/object-utils.js:244:31)
    at /project-path/node_modules/istanbul/lib/collector.js:71:44
    at Array.forEach (native)
    at Object.Collector.add (/project-path/node_modules/istanbul/lib/collector.js:68:31)
    at /project-path/node_modules/istanbul/lib/command/check-coverage.js:125:27
    at Array.forEach (native)
    at /project-path/node_modules/istanbul/lib/command/check-coverage.js:123:19
    at /project-path/node_modules/istanbul/lib/util/file-matcher.js:39:20

Using karma, browserify-istanbul and istanbul (v0.4.0) to check the coverage files. Has anyone seen this before?

[domharrington]

My issue was resolved by removing my node_modules folder and reinstalling everything. I've got no idea why.

[CapitanRedBeard]

Still seeing this issue using Jest Client 0.7.1 with Istanbul 0.3.22 along with RN 22

[VishalAkhouri]

I am also getting similar issue (using karma-cli v3.8.9)

 PROJECT_PATH\node_modules\istanbul\lib\object-utils.js:247
             for (i = 0; i < retArray.length; i += 1) {
                                     ^

 TypeError: Cannot read property 'length' of undefined
     at PROJECT_PATH\node_modules\istanbul\lib\object-utils.js:247:37
     at Array.forEach (native)
     at Object.mergeFileCoverage (PROJECT_PATH\node_modules\istanbul\lib\object-utils.js:244:31)
     at PROJECT_PATH\node_modules\istanbul\lib\collector.js:71:44
     at Array.forEach (native)
     at Object.Collector.add (PROJECT_PATH\node_modules\istanbul\lib\collector.js:68:31)
     at PROJECT_PATH\node_modules\istanbul\lib\command\check-coverage.js:125:27
     at Array.forEach (native)
     at PROJECT_PATH\node_modules\istanbul\lib\command\check-coverage.js:123:19
     at PROJECT_PATH\node_modules\istanbul\lib\util\file-matcher.js:39:20
     at Object.next (PROJECT_PATH\node_modules\fileset\lib\fileset.js:43:14)
     at emitOne (events.js:96:13)
     at Fileset.emit (events.js:188:7)
     at Fileset.Glob._finish (PROJECT_PATH\node_modules\fileset\node_modules\glob\glob.js:172:8)
     at done (PROJECT_PATH\node_modules\fileset\node_modules\glob\glob.js:159:12)
     at Fileset.Glob._processGlobStar2 (PROJECT_PATH\node_modules\fileset\node_modules\glob\glob.js:601:12)

 Process finished with exit code 1

Resolution: To resolve the issue I had to do gulp clean, probably there was some artifact leftover by karma that was causing the issue. Just removing the node_modules did not work for me.

[CapitanRedBeard]

I have removed and reinstalled node_modules a dozen times and I still get this issue.

[domharrington]

Have you tried doing a fresh clone of the project? Do you have any globally installed node_modules which may be screwing with any versions of modules? Have you removed the coverage files?

[ghost]

I'm using Istanbul 0.4.4 and Mocha 2.5.3 and I keep hitting this issue, tried reinstalling all of the node_modules and deleting and re-cloning the project and I'm still getting this error.

[cvbuelow]

Was having the same issue but deleting my coverage folder fixed it.

[reggi]

I removed the --all flag from NYC and it fixed it.

[ardok]

UPDATES MAR 15 16:41

I had reporter.addAll(['json', 'text', 'lcov', 'cobertura']);
I just needed to remove lcov and it works just fine.

---

@reggi how do you remove the --all ?

I'm facing the same issue:

<project-path>/node_modules/istanbul/lib/object-utils.js:247
            for (i = 0; i < retArray.length; i += 1) {
                                    ^

TypeError: Cannot read property 'length' of undefined
    at <project-path>/node_modules/istanbul/lib/object-utils.js:247:37

I'm using jest and the error happens when I have this:

  "collectCoverageFrom": [
    "!**/node_modules/**",
    "<rootDir>/src/client/**/*.js",
    "<rootDir>/src/server/**/*.js",
    "<rootDir>/src/shared/**/*.js"
  ],

When I do it without collectCoverageFrom, it works just fine but it only collects from the files that is being tested, which would provide incorrect coverage from.

[annisuu]

Removing the coverage folder did the trick for me. -.-