angular ng serve command throws error: An unhandled exception occurred: Project does not exist

Question

I am trying to up my local angular dev env using ng serve, it was working perfectly fine a day back, but now every time I run ng serve or npm start it throws an error:

An unhandled exception occurred: Project does not exist.

I have tried running ng serve in one of my different project, it works there.

not sure what it causing this error

Answer 1

Make sure the name of the project in your angular.json matches what is being called from your package.json scripts section.

This is how I discovered the problem. I was getting the following error:

An unhandled exception occurred: Project does not exist.
See "C:\Users\Adam\AppData\Local\Temp\ng-XcQsPs\angular-errors.log" for further details.

When I went to that log file, I saw this:

[error] Error: Project does not exist.
    at WorkspaceNodeModulesArchitectHost.findProjectTarget (C:\Users\Adam\source\repos\TechScore.Express\node_modules\@angular-devkit\architect\node\node-modules-architect-host.js:94:23)
    at WorkspaceNodeModulesArchitectHost.getBuilderNameForTarget (C:\Users\Adam\source\repos\TechScore.Express\node_modules\@angular-devkit\architect\node\node-modules-architect-host.js:13:39)
    at RunCommand.runSingleTarget (C:\Users\Adam\source\repos\TechScore.Express\node_modules\@angular\cli\models\architect-command.js:175:55)
    at RunCommand.runArchitectTarget (C:\Users\Adam\source\repos\TechScore.Express\node_modules\@angular\cli\models\architect-command.js:218:35)
    at RunCommand.run (C:\Users\Adam\source\repos\TechScore.Express\node_modules\@angular\cli\commands\run-impl.js:14:25)
    at RunCommand.validateAndRun (C:\Users\Adam\source\repos\TechScore.Express\node_modules\@angular\cli\models\command.js:134:39)
    at process._tickCallback (internal/process/next_tick.js:68:7)
    at Function.Module.runMain (internal/modules/cjs/loader.js:834:11)
    at startup (internal/bootstrap/node.js:283:19)
    at bootstrapNodeJSCore (internal/bootstrap/node.js:622:3)

So I opened node-modules-architect-host.js:94:23 and saw this:

const projectDefinition = this._workspace.projects.get(target.project);
if (!projectDefinition) {
    throw new Error('Project does not exist.');
}

I have no idea why they throw an error like this without telling you which project does not exist. So I changed the file to be like this:

throw new Error('Project does not exist. ' + target.project);

Now, when I build, I get an error like this instead:

An unhandled exception occurred: Project does not exist. client-app

Finally I can see who the culprit is! A global search for "client-app" showed me that it was being used from package.json, but my project in angular.json was "ClientApp". Changing all references of "ClientApp" to "client-app" fixed the problem for me.