No type info without type option

The simple @JsonMember doesn’t work, I have error "No valid 'type' option was specified for 'DatabaseConfig.password'". I have to use:

@JsonMember({ type: String })
firstName: string;

In my package.json:

"dependencies": {
    "reflect-helper": "^1.0.2",
    "reflect-metadata": "^0.1.8",
  },

In my tsconfig.json:

"compilerOptions": {
        "experimentalDecorators": true,
        "emitDecoratorMetadata": true,
}

What else I have to do to make it work like in sample?

@JsonObject
class Person {
    @JsonMember
    firstName: string;

    @JsonMember
    lastName: string;

    public getFullname() {
        return this.firstName + " " + this.lastName;
    }
}

[MichalLytek]

Why the node_modules instalation doesn’t work? I have even typescript compiler running from it to be able to deploy app easy - all dependencies are defined in package.json so npm install and go.

[MichalLytek]

All we need to do is to place import "reflect-metadata"; on top of the entry file 😉

Closing this issue because now I use class-transformer.