Nest.js and Angular.js monorepo: trying to share library folder

Question

I am trying to share models and functions between two typescript projects (nest.js and angular.js). I just created boilerplate nest.js and angular.js projects in api and ui respectively and a folder called lib containing one typescript file. Angular doesn't have a problem importing typescript files from an upper folder. But nest.js fails with this error:

➜  api git:(master) npm run start

> [email protected] start
> nest start

Error: Cannot find module '/home/amir/workspace/nest-angular-monorepo/api/dist/main'
    at Function.Module._resolveFilename (node:internal/modules/cjs/loader:956:15)
    at Function.Module._load (node:internal/modules/cjs/loader:804:27)
    at Function.executeUserEntryPoint [as runMain] (node:internal/modules/run_main:81:12)
    at node:internal/main/run_main_module:17:47
npm ERR! Lifecycle script `start` failed with error: 
npm ERR! Error: command failed 
npm ERR!   in workspace: [email protected] 
npm ERR!   at location: /home/amir/workspace/nest-angular-monorepo/api 
➜  api git:(master) 

Repository

Answer 1

Here I created a diff, to apply copy it into a file patch.diff and apply git apply patch.diff:

diff --git a/api/package.json b/api/package.json
index cc378ed..6e1db4e 100644
--- a/api/package.json
+++ b/api/package.json
@@ -1,5 +1,5 @@
 {
-  "name": "api",
+  "name": "@root/api",
   "version": "0.0.1",
   "description": "",
   "author": "",
@@ -24,7 +24,8 @@
     "@nestjs/core": "^9.0.0",
     "@nestjs/platform-express": "^9.0.0",
     "reflect-metadata": "^0.1.13",
-    "rxjs": "^7.2.0"
+    "rxjs": "^7.2.0",
+    "@root/shared": "*"
   },
   "devDependencies": {
     "@nestjs/cli": "^9.0.0",
diff --git a/api/src/main.ts b/api/src/main.ts
index d002cd5..ac2dfb3 100644
--- a/api/src/main.ts
+++ b/api/src/main.ts
@@ -1,6 +1,6 @@
 import { NestFactory } from '@nestjs/core';
 import { AppModule } from './app.module';
-import { User } from '../../lib/model';
+import { User } from '@root/shared/model';
 
 const usr: User = { name: 'mair' };
 console.log(usr);
diff --git a/lib/package.json b/lib/package.json
new file mode 100644
index 0000000..e777951
--- /dev/null
+++ b/lib/package.json
@@ -0,0 +1,3 @@
+{
+  "name": "@root/shared"
+}
diff --git a/package-lock.json b/package-lock.json
index b78f779..e0f10e9 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -15,12 +15,14 @@
       ]
     },
     "api": {
+      "name": "@root/api",
       "version": "0.0.1",
       "license": "UNLICENSED",
       "dependencies": {
         "@nestjs/common": "^9.0.0",
         "@nestjs/core": "^9.0.0",
         "@nestjs/platform-express": "^9.0.0",
+        "@root/shared": "*",
         "reflect-metadata": "^0.1.13",
         "rxjs": "^7.2.0"
       },
@@ -7317,19 +7319,22 @@
       }
     },
     "lib": {
-      "version": "1.0.0",
-      "extraneous": true,
-      "license": "ISC"
+      "name": "@root/shared"
     },
-    "node_modules/api": {
+    "node_modules/@root/api": {
       "resolved": "api",
       "link": true
     },
-    "node_modules/ui": {
+    "node_modules/@root/shared": {
+      "resolved": "lib",
+      "link": true
+    },
+    "node_modules/@root/ui": {
       "resolved": "ui",
       "link": true
     },
     "ui": {
+      "name": "@root/ui",
       "version": "0.0.0",
       "dependencies": {
         "@angular/animations": "^15.2.0",
@@ -7340,6 +7345,7 @@
         "@angular/platform-browser": "^15.2.0",
         "@angular/platform-browser-dynamic": "^15.2.0",
         "@angular/router": "^15.2.0",
+        "@root/shared": "*",
         "rxjs": "~7.8.0",
         "tslib": "^2.3.0",
         "zone.js": "~0.12.0"
diff --git a/ui/package.json b/ui/package.json
index 67d64b8..f227b68 100644
--- a/ui/package.json
+++ b/ui/package.json
@@ -1,5 +1,5 @@
 {
-  "name": "ui",
+  "name": "@root/ui",
   "version": "0.0.0",
   "scripts": {
     "ng": "ng",
@@ -20,7 +20,8 @@
     "@angular/router": "^15.2.0",
     "rxjs": "~7.8.0",
     "tslib": "^2.3.0",
-    "zone.js": "~0.12.0"
+    "zone.js": "~0.12.0",
+    "@root/shared": "*"
   },
   "devDependencies": {
     "@angular-devkit/build-angular": "^15.2.7",
diff --git a/ui/src/app/app.component.ts b/ui/src/app/app.component.ts
index c276b9a..0fe97c2 100644
--- a/ui/src/app/app.component.ts
+++ b/ui/src/app/app.component.ts
@@ -1,5 +1,5 @@
 import { Component } from '@angular/core';
-import {User} from "../../../lib/model";
+import { User } from '@root/shared/model';
 
 @Component({
   selector: 'app-root',

You can rename the package names however you like I named them @root/ui, @root/shared and @root/api

Edit:

If you look under node_modules/@root/ you will see that npm only creates links to your packages.