TypeError: Cannot read property 'length' of undefined, when karma tests re-load

[jschank]

This bug report is from using Angular2 and Karma/Jasmine
But the error is emitted from Typescript. I am hoping that is the relevant part.

Versions

    _                      _                 ____ _     ___
   / \   _ __   __ _ _   _| | __ _ _ __     / ___| |   |_ _|
  / △ \ | '_ \ / _` | | | | |/ _` | '__|   | |   | |    | |
 / ___ \| | | | (_| | |_| | | (_| | |      | |___| |___ | |
/_/   \_\_| |_|\__, |\__,_|_|\__,_|_|       \____|_____|___|
               |___/

Angular CLI: 1.6.5
Node: 8.7.0
OS: darwin x64
Angular: 4.3.6
... animations, common, compiler, compiler-cli, core, forms
... http, language-service, platform-browser
... platform-browser-dynamic, router, tsc-wrapped

@angular/.DS_Store: error
@angular/cli: 1.6.5
@angular-devkit/build-optimizer: 0.0.41
@angular-devkit/core: 0.0.28
@angular-devkit/schematics: 0.0.51
@ngtools/json-schema: 1.1.0
@ngtools/webpack: 1.9.5
@schematics/angular: 0.1.16
typescript: 2.3.4
webpack-bundle-analyzer: 2.9.2
webpack: 3.10.0

----
Some more versions that might be helpful

        "jasmine-core": "^2.99.1",
        "jasmine-expect": "^3.8.3",
        "jasmine-matchers": "^0.2.3",
        "jasmine-spec-reporter": "~4.1.0",
        "karma": "~1.7.0",
        "karma-chrome-launcher": "^2.2.0",
        "karma-cli": "~1.0.1",
        "karma-coverage-istanbul-reporter": "^1.2.1",
        "karma-jasmine": "^1.1.1",
        "karma-jasmine-html-reporter": "^0.2.2",
        "karma-jasmine-matchers": "^3.7.0",

I am using macOS Sierra, 10.12.6

Repro steps

When I run $ npm run test, my tests pass fine.
But if I then save one of my spec files (even if I don't change it)
Then a new run is kicked off, but always produces this error:

Observed behavior

ERROR in TypeError: Cannot read property 'length' of undefined
    at createSourceFile (/Users/jschank/ddc-advocacy/projects/ddca-iceland/node_modules/typescript/lib/typescript.js:15464:110)
    at parseSourceFileWorker (/Users/jschank/ddc-advocacy/projects/ddca-iceland/node_modules/typescript/lib/typescript.js:15389:26)
    at Object.parseSourceFile (/Users/jschank/ddc-advocacy/projects/ddca-iceland/node_modules/typescript/lib/typescript.js:15338:26)
    at Object.createSourceFile (/Users/jschank/ddc-advocacy/projects/ddca-iceland/node_modules/typescript/lib/typescript.js:15192:29)
    at new TypeScriptFileRefactor (/Users/jschank/ddc-advocacy/projects/ddca-iceland/node_modules/@ngtools/webpack/src/refactor.js:79:35)
    at Object.findLazyRoutes (/Users/jschank/ddc-advocacy/projects/ddca-iceland/node_modules/@ngtools/webpack/src/lazy_routes.js:18:22)
    at AotPlugin._findLazyRoutesInAst (/Users/jschank/ddc-advocacy/projects/ddca-iceland/node_modules/@ngtools/webpack/src/plugin.js:217:50)
    at _donePromise.Promise.resolve.then.then.then.then.then (/Users/jschank/ddc-advocacy/projects/ddca-iceland/node_modules/@ngtools/webpack/src/plugin.js:496:24)
    at <anonymous>
    at process._tickCallback (internal/process/next_tick.js:188:7)

Desired behavior

Saving my spec files should result in karma tests being run again. (I know that isn't the responsibility of this repo. But the error Appears to me to be in Typescript)

Mention any other details that might be useful (optional)

Most of the googling about this error, leads to the advice of putting a console.log(fileName); statement. To dump the offending file to the console.
When I look at that location, I see this

function createSourceFile(fileName, languageVersion, scriptKind) {
	// code from createNode is inlined here so createNode won't have to deal with special case of creating source files
	// this is quite rare comparing to other nodes and createNode should be as fast as possible
	var sourceFile = new SourceFileConstructor(265 /* SourceFile */, /*pos*/ 0, /* end */ sourceText.length);
	nodeCount++;
	sourceFile.text = sourceText;
	sourceFile.bindDiagnostics = [];
	sourceFile.languageVersion = languageVersion;
	sourceFile.fileName = ts.normalizePath(fileName);
	sourceFile.languageVariant = getLanguageVariant(scriptKind);
	sourceFile.isDeclarationFile = ts.fileExtensionIs(sourceFile.fileName, ".d.ts");
	sourceFile.scriptKind = scriptKind;
	return sourceFile;
}

It looks to me, like the problem is that sourceText, is undefined. And we're calling length on it here.
If I reset the sourceText to an empty string, when it is undefined or null. My tests re-run on changes, with no errors.
Unfortunately, I have no idea if that is a reasonable solution to the problem.

function createSourceFile(fileName, languageVersion, scriptKind) {
	if (!sourceText) {
		// console.log("*** Filename: ", fileName);
		// console.log("*** languageVersion: ", languageVersion);
		// console.log("*** scriptKind: ", scriptKind);
		// Note: this seems to allow the typescript parser to continue when a file is updated
		sourceText = "";
	}
	// code from createNode is inlined here so createNode won't have to deal with special case of creating source files
	// this is quite rare comparing to other nodes and createNode should be as fast as possible
	var sourceFile = new SourceFileConstructor(265 /* SourceFile */, /*pos*/ 0, /* end */ sourceText.length);
	nodeCount++;
	sourceFile.text = sourceText;
	sourceFile.bindDiagnostics = [];
	sourceFile.languageVersion = languageVersion;
	sourceFile.fileName = ts.normalizePath(fileName);
	sourceFile.languageVariant = getLanguageVariant(scriptKind);
	sourceFile.isDeclarationFile = ts.fileExtensionIs(sourceFile.fileName, ".d.ts");
	sourceFile.scriptKind = scriptKind;
	return sourceFile;
}

[mhamel06]

Been trying to track down the exact cause of this error as well. In the meantime, it appears that 1.6.1 does not have this bug.

Duplicate issues:
#9331
#5053

[mexican-plumber]

Been fighting with the same problem for a few weeks and finally got the chance to do something about it - finally got it sorted.
I believe that part of the problem was because the 'app' folder had been moved to the same level as the 'src' (which was deleted) and also because the 'app' folder was also renamed 'App'.
So anyway I created a brand new angular app and reproduced the folder related steps, which broke the app to a degree, but managed to get it all working again.
From that point i started comparing the files on my real app with the dummy app and after some effort i have it working perfectly.
One thing that i realised (note that im working on Windows, which is case insensitive when it comes to paths), was that some of my import statements didnt all have the correct case - apparently 'app/some-component' and 'App/some-component' aren't really the same. This led me normalise my folder names to kebab-case and it solved part of the problem.
The only catch in the middle of all of this is that i ended up upgrading from angular 4 to 5.

Hope this helps anyone with the same type of issue (only took me around a day and a half to get it sorted lol)

Current version:

Angular CLI: 1.6.8
Node: 8.9.4
OS: win32 x64
Angular: 5.2.4
... animations, common, compiler, compiler-cli, core, forms
... http, language-service, platform-browser
... platform-browser-dynamic, router

@angular/cli: 1.6.8
@angular-devkit/build-optimizer: 0.0.42
@angular-devkit/core: 0.0.29
@angular-devkit/schematics: 0.0.52
@ngtools/json-schema: 1.1.0
@ngtools/webpack: 1.9.8
@schematics/angular: 0.1.17
typescript: 2.5.3
webpack: 3.11.0

[uweDuesing]

The same problem occurs with Angular CLI version 1.7.1

[davcri]

Same here on Ubuntu 17.10 (4.13.0-36-generic).
I also tried updating node, but it didn't fix the issue.

Angular CLI: 1.7.1
Node: 6.11.4
OS: linux x64
Angular: 4.4.6
... animations, common, compiler, compiler-cli, core, forms
... http, language-service, platform-browser
... platform-browser-dynamic, router, tsc-wrapped

@angular/cli: 1.7.1
@angular-devkit/build-optimizer: 0.3.2
@angular-devkit/core: 0.3.2
@angular-devkit/schematics: 0.3.2
@ngtools/json-schema: 1.2.0
@ngtools/webpack: 1.10.1
@schematics/angular: 0.3.2
@schematics/package-update: 0.3.2
typescript: 2.7.2
webpack: 3.11.0

[Adam-Pond]

As identified in #5053, downgrading Angular CLI to 1.6.0 works. Seems to be a known issue

npm uninstall -g @angular/cli
npm uninstall --save-dev @angular/cli
npm install -g @angular/cli@1.6.0

rmdir /s node_modules
npm install --save-dev @angular/cli@1.6.0
npm install

[SergeyShurygin]

I have the same error with cli 1.6.8

I've done some debugging and figured out that problem is in the next line in
\node_modules@ngtools\webpack\src\plugin.js file:

const changedFilePaths = this._compilerHost.getChangedFilePaths();

in 1.6.0 version getChangedFilePaths returns only several files ( [ '../app/src/polyfills.ts',
'../app/node_modules/classlist.js/package.json',
'../app/src/app/data-models/store/test.side-effects.spec.ts' ], but in 1.6.8 it returns them all plus '../app/src/' directory, which does not have any sourceText and cause the mentioned error

[uchitha]

I have encountered the same issue with 1.6.5, 1.7.4 (latest) and 1.6.0 (downgraded as per suggested above). It's caused by exactly the same reason as suggested by @SergeyShurygin above. Any update on this would be awesome as I can't afford to patch node modules from public registry.

[johngrimsey]

Same here, downgrade from 1.7.4 to 1.6.0 needed to avoid the issue when watching tests

[davcri]

Update: now it's working fine for me with ng test.

Angular CLI: 1.7.4
Node: 6.11.4
OS: linux x64
Angular: 5.2.9

---

These days I'm using Angular CLI: 1.7.4 with ng test --watch --poll 256 -sm=false and it's working as expected.
I haven't tried ng test in a while.

[paulmelero]

Please. There's no need to delete node_modules. This issue happens for a mismatch between you global @angular/cli, the angular tools (installed locally) and typescrypt (installed locally, also).

I would recommend to run:

npm update # do it at your own risk: it updates everything! If you have versions specified with `^` this may break your code
npm i -g @angular/cli@latest # global
npm i typescript@latest # or the one that `@angular/compiler-cli` says whenever you start the application (`ng serve --aot` or whatever)

And before running the tests, make a compilation to avoid fixing things in the @ngtools/webpack on your own.

Just tested this in production when I switched to my master branch and those errors appeared.

Take into consideration adding npm i -g @angular/cli@latest to the postinstall of your npm scripts.

What @Adam-Pond suggested will only work if you are lucky and the three breaking points I mentioned are in harmony.

Hope it helps! 🐋