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.

Answer 2

Similar to issue mentioned by adam0101, the issue got fixed for me by changing the project name. Infact package.json and angular.json names can be different( at least for me), but within angular.json, the naming was consistent

Old

  "$schema": "./node_modules/@angular/cli/lib/config/schema.json",
  "version": 1,
  "newProjectRoot": "projects",
  "projects": {
    "e-admin": {   ======NAME USED HERE=======
      "root": "",
...
"serve": {
          "builder": "@angular-devkit/build-angular:dev-server",
          "options": {
            "browserTarget": "eAdmin:build"    ===NAME USED HERE====
          },
          "configurations": {
            "production": {
              "browserTarget": "eAdmin:build:production"  <===NAME USED HERE
            }
          }
        },

Modified

 "$schema": "./node_modules/@angular/cli/lib/config/schema.json",
  "version": 1,
  "newProjectRoot": "projects",
  "projects": {
    "e-admin": {
      "root": "",
...
"serve": {
          "builder": "@angular-devkit/build-angular:dev-server",
          "options": {
            "browserTarget": "e-admin:build"
          },
          "configurations": {
            "production": {
              "browserTarget": "e-admin:build:production"
            }
          }
        },

Answer 3

please check projects name and defaultProject are same

testapp

{
"$schema": "./node_modules/@angular/cli/lib/config/schema.json",
"version": 1,
"newProjectRoot": "projects",
"projects": { // here 
    "testapp": {
        "root": "",
        "sourceRoot": "src",
        "projectType": "application",

.....................

"defaultProject": "testapp",

please try

npm install 

or

yarn install