typeorm: Column type for UserModel#userId is not defined and cannot be guessed. Make sure you have turned on an "emitDecoratorMetadata": true option in tsconfig.json.

@Column() must set a type,like @Column('text',{nullable:true})

In your tsconfig.json, you can explicitly specify "strict": false, to disable strict type-checking.

Set the following in tsconfig.json

"emitDecoratorMetadata": true,

and

"strict": false,

Hello, i’ve built a plugin to compile runtime metadata information from TypeScript even if using @babel/preset-typescript instead of TSC. Not sure if this is your problem, but in case you can try: https://github.com/leonardfactory/babel-plugin-transform-typescript-metadata#readme

Elseway as @shouhuori suggested you can just type the colum type

Hi. I just ran into this issue and fixed it. When I had the issue, my entity looked like this:

import { Entity, PrimaryColumn, Column } from "typeorm/browser";

@Entity("tenant")
export class Tenant {

  @PrimaryColumn()
  id!: number;

  @Column()
  unitNumber!: number;

  @Column()
  blockNumber!: number;

  @Column()
  fullName!: string;
}

And like @shouhuori mentioned, a type must be added to the column. And that fixed it:

@Entity("tenant")
export class Tenant {

  @PrimaryColumn("int")
  id!: number;

  @Column("int")
  unitNumber!: number;

  @Column("int")
  blockNumber!: number;

  @Column("text")
  fullName!: string;
}

From my understanding the type is required in the annotation for the database, while the other type below it is for typescript inference.

Thanks @leonardfactory for that package, it solved the problem for me!

to add to that - I found that it only worked when using the legacy decorator plugin for babel:

    plugins: [
      'babel-plugin-transform-typescript-metadata',
      ["@babel/plugin-proposal-decorators", { "legacy": true }],
      ["@babel/plugin-proposal-class-properties", { "loose" : true }]
    ],

Adding a attributes in tsconfig.ts solved my problem: “emitDecoratorMetadata”: true You can refer details from api https://www.typescriptlang.org/docs/handbook/compiler-options.html

In my case I accidentally had an extra @Column decorator

@Column() <--- 
@ManyToOne(
  () => User,
  user => user.videos,
)
@JoinColumn({ name: 'uploaded_by_id' })
uploaded_by: User

tbh none of the above solutions worked for me. What worked was clearing all the generated files under /dist and rebuilding the project.

I’m sure a noob like me will reach here sometime and it will help them 😄

My issue was with PrimaryColumn

I fixed it like:

@Entity("tenant")
export class Tenant {
  @PrimaryColumn("int")
  id!: number;
  ...
}

@leonardfactory, that fixed the error I was having using typeorm with nextjs (which is using babel). Thanks!

Adding types everywhere eventually helped in my case, like @Column('varchar'), @Column('integer')

I have this issue tsconfig.json

...
    "emitDecoratorMetadata": true,
    "experimentalDecorators": true,   
...

app.ts

import "reflect-metadata";

import { DataSource } from "typeorm";
import { Entity, Column, PrimaryGeneratedColumn } from "typeorm";

@Entity()
export class Photo {
  @PrimaryGeneratedColumn()
  id: number;

  @Column()
  name: string;

  @Column()
  description: string;

  @Column()
  filename: string;

  @Column()
  views: number;

  @Column()
  isPublished: boolean;
}

const AppDataSource = new DataSource({
  type: "postgres",
  host: "localhost",
  port: 5432,
  username: "root",
  password: "admin",
  database: "test",
  entities: [Photo],
  synchronize: true,
  logging: true,
});

AppDataSource.initialize()
  .then(() => {
  })
  .catch((error) => console.log(error));

It makes absolutely no sense. I have tried doing everything in this issue to no avail. I don’t want to specify types manually.

ColumnTypeUndefinedError: Column type for Photo#name is not defined and cannot be guessed. Make sure you have turned on an “emitDecoratorMetadata”: true option in tsconfig.json. Also make sure you have imported “reflect-metadata” on top of the main entry file in your application (before any entity imported).If you are using JavaScript instead of TypeScript you must explicitly provide a column type.

I don’t know whether it can help you but for me it was I just complied my NodeJS project typescript files like this: tsc src/**/* which resulted in this error. When I‌ just removed my .js files in the src folder, everything worked just fine.

I‌ should mention that tracking the error helped me a lot. To do that find node_modules/typeorm/error/ColumnTypeUndefinedError.js file and in ColumnTypeUndefinedError function before return _this; add console.log(_this); or whatever log you use. This will show the entire error including stack, instead of only message.

Hope it could help you.

@Column() must set a type,like @Column('text',{nullable:true})

fixed in the TypeOrm 0.3.12 with Serverless 3.27. Thank You

In my case it was just a stupid copy paste error, might be your case too:

@Column()  // this should not be here as we only use OneToMany instead of Column()
@OneToMany(() => Review, (review) => review.book)

I was using both of them together

I hope that helps

with this code run for me

tsc .\src\index.ts --experimentalDecorators "true" --emitDecoratorMetadata "true"

I solved my problem at class definition, I forgot to set user_id field on File.ts:

@ManyToOne(() => User, (user) => user.files)
@JoinColumn({ name: 'user_id' })
user: User;

Do you mind posting a sample project gist, or a trivial example? Nothing from what you posted looks wrong to my eyes, but it may be that you are missing something in your source code. For example import "reflect-metadata"; in the entry point before importing entities, etc.

Thanks @leonardfactory for that package, it solved the problem for me!

to add to that - I found that it only worked when using the legacy decorator plugin for babel:

    plugins: [
      'babel-plugin-transform-typescript-metadata',
      ["@babel/plugin-proposal-decorators", { "legacy": true }],
      ["@babel/plugin-proposal-class-properties", { "loose" : true }]
    ],

Its working, thanks dude ❤️