作为表达式调用时无法解析属性装饰器的签名

Question

import { isEmail, isEmpty, isPhoneNumber, Length } from "class-validator"
import { Field, InputType } from "type-graphql";

@InputType()
export class RegisterInput {
    @Field()
    @Length(2, 15, { message: "Username Must Be At Least 2 characters" })
    username?: string;

    @Field()
    @isEmail()
    email?: string;

    @Field()
    @Length(1, 20)
    @isPhoneNumber()
    phoneNumber?: string;

    @isEmpty()
    password?: string

}

问题是 @isEmail() 和 @isPhoneNumber() 和 @isEmpty() 抛出相同的错误：

Unable to resolve signature of property decorator when called as an expression.
  This expression is not callable.
    Type 'Boolean' has no call signatures.ts(1240)

请帮帮我，我一整天都被这个错误困扰了

Answer 1

你必须用大写字母来书写这些装饰器。TypeScript 区分大小写：

import { IsEmail, IsEmpty, IsPhoneNumber, Length } from "class-validator";

@Field()
@IsEmail()
email?: string;

@Field()
@Length(1, 20)
@IsPhoneNumber()
phoneNumber?: string;

@IsEmpty()
password?: string

Answer 2

您可能需要将此属性添加到tsconfig.json文件中的属性下compilerOptions：

"experimentalDecorators": true

感谢 Technical Rajni 提供的 YouTube 视频解决方案，请参见此处。