NodeJS problems with imports when transpiling from typescript

Question

I have implemented simple rest api with nodejs and connection to database via typeorm. Here are some snippets of code which I wrote:

import {
  Entity,
  PrimaryGeneratedColumn,
  Column,
  Unique,
  CreateDateColumn,
  UpdateDateColumn
} from "typeorm";
import { Length, IsNotEmpty } from "class-validator";
import bcrypt from "bcryptjs";

@Entity()
@Unique(["username"])
export class User {
  @PrimaryGeneratedColumn()
  public id: number;

  @Column()
  @Length(4, 20)
  username: string;
}

tsconfig.json

{
    "compilerOptions": {
        "experimentalDecorators": true,
        "module": "commonjs",
        "esModuleInterop": true,
        "target": "es6",
        "moduleResolution": "node",
        "sourceMap": true,
        "outDir": "dist",
        "emitDecoratorMetadata": true
    },
    "lib": [
        "es2015"
    ]
}

package.json

{
    "name": "node-with-ts",
    "version": "1.0.0",
    "description": "",
    "main": "dist/app.js",
    "scripts": {
        "start": "tsc && node dist/app.js",
        "test": "echo \"Error: no test specified\" && exit 1",
        "tsc": "tsc",
        "prod": "node ./dist/app.js",
        "build": "npm install && tsc -p .",
        "reset": "rm -rf node_modules/ && rm -rf dist/ && npm run build",
        "migration:run": "ts-node ./node_modules/typeorm/cli.js migration:run"
    },
    "author": "",
    "license": "ISC",
    "devDependencies": {
        "@types/express": "^4.16.1",
        "@types/node": "^12.7.5",
        "nodemon": "^1.19.2",
        "ts-node": "8.4.1",
        "tslint": "^5.12.1",
        "typescript": "^3.3.3"
    },
    "dependencies": {
        "@types/bcryptjs": "^2.4.2",
        "@types/body-parser": "^1.17.0",
        "@types/cors": "^2.8.4",
        "@types/helmet": "0.0.42",
        "@types/jsonwebtoken": "^8.3.0",
        "bcryptjs": "^2.4.3",
        "body-parser": "^1.18.1",
        "class-validator": "^0.9.1",
        "cors": "^2.8.5",
        "express": "4.17.1",
        "helmet": "^3.21.1",
        "jsonwebtoken": "^8.4.0",
        "reflect-metadata": "^0.1.13",
        "sqlite3": "^4.1.0",
        "ts-node-dev": "^1.0.0-pre.32",
        "typeorm": "^0.2.12"
    }
}

I have pasted lots of code because I have no idea what is wrong. I am tryinf to run app via npm run start and it throws below error:

> tsc && node dist/app.js

    /Users/workspace/node_typescript_project/src/entity/User.ts:1
    (function (exports, require, module, __filename, __dirname) { import {
                                                                  ^^^^^^

    SyntaxError: Unexpected token import

Although I able to build to project and it generates js codes but when it comes to run application it throws errors.

Can you give us your node version ? In a terminal node -v. Your issue is that import is a ES6 keyword, and your node version seems to not handle this. — Richard Haddad
– Richard Haddad, Commented Sep 28, 2019 at 19:26

raychz · Accepted Answer · 2019-10-01 01:45:15Z

Your entities are probably not being referenced correctly in your Typeorm config file.

Try to see if you can get it to work with the following ormconfig.js file (pay special attention to the entities property:

// ormconfig.js at root of project
const isDevelopment = process.env.NODE_ENV === 'development';
module.exports = {
  type: 'mysql',
  host: process.env.MYSQL_HOST,
  port: process.env.MYSQL_TCP_PORT,
  username: process.env.MYSQL_USER,
  password: process.env.MYSQL_PASSWORD,
  database: process.env.MYSQL_DATABASE,
  synchronize: isDevelopment,
  logging: isDevelopment,
  entities: [
    isDevelopment ? `src/**/*.entity.ts` : `dist/**/*.entity.js`,
  ],
  migrations: [`src/migration/**/*.ts`],
  subscribers: ['src/subscriber/**/*.ts'],
  cli: {
    entitiesDir: 'src/entity',
    migrationsDir: 'src/migration',
    subscribersDir: 'src/subscriber',
  },
};

With this setup, I have ts-node working directly with my Typescript source files, and only in production do I use tsc to build. When building for prod, I need to reference the .js files inside of the dist folder.

pktippa · Accepted Answer · 2019-09-28 17:04:02Z

0

I am trying to replicate the issue but couldn't replicate it. Just created a sample repo for above code.

https://github.com/pktippa/stackoverflow-questions/tree/master/58148222

answered Sep 28, 2019 at 17:04

pktippa

763 silver badges9 bronze badges

3 Comments

Jan Testowy Over a year ago

Why do you have Babel in your package lock json?

Jan Testowy Over a year ago

And which node and npm do you have?

pktippa Over a year ago

babel got installed because of tslint requires it and, tslint is a devDependency in the package.json. OS: Windows 10 Pro NodeJs: 8.15.0 NPM: 6.7.0

Tammar · Accepted Answer · 2019-09-28 17:21:00Z

0

Try a different import syntax, eg.: import { bcrypt } from "bcryptjs";

Other import syntax examples can be found here.

answered Sep 28, 2019 at 17:21

Tammar

111 silver badge3 bronze badges

Comments

Richard Haddad · Accepted Answer · 2019-09-28 21:08:49Z

0

Node.js does not handle ES6 syntax, with imports etc. For that you have to transpile your ES6 code to ES5, you can do it with Babel => https://github.com/babel/example-node-server

If you don't want to use Babel, you can simply replace import by require:

const bcrypt = require("bcryptjs");  // same as 'import * as bcrypt from "bcryptjs";'

answered Sep 28, 2019 at 21:08

Richard Haddad

1,0247 silver badges13 bronze badges

1 Comment

Ferrybig Over a year ago

Node only handles es6 when used with mjs files, and the experimental flag turned on.

Collectives™ on Stack Overflow

NodeJS problems with imports when transpiling from typescript

4 Answers 4

Comments

3 Comments

Comments

1 Comment

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

4 Answers 4

Comments

3 Comments

Comments

1 Comment

Your Answer

Sign up or log in

Post as a guest

Related