Questions tagged [reflect-metadata]
83 questions
106
votes
2 answers
What is reflect-metadata in typescript
what are reflect-metadata and its purpose?
What is syntax and purpose of using reflect-metadata?
Can some one provide the example for better understanding of the same?
How can be the reflect metadata helpful in implementing decorators in typescript.
Mantu Nigam
- 3,690
- 7
- 24
- 41
25
votes
2 answers
typeORM: "message": "Data type \"Object\" in \"..." is not supported by \"postgres\" database."
Given the following entity definition:
@Entity()
export class User extends BaseEntity {
@Column({ nullable: true })
name!: string | null;
@Column()
age!: number;
}
The following error appears:
typeORM: "message": "Data type \"Object\"…
silicakes
- 6,364
- 3
- 28
- 39
12
votes
1 answer
What's the difference between Reflect.getMetadata and Reflect.getOwnMetadata?
As said in the title: the reflect-metadata API provides a getMetadata method and a getOwnMetadata - what's the difference here? Same goes for hasOwnMetadata, etc.
nehalist
- 1,434
- 18
- 45
10
votes
1 answer
Why does TypeORM need reflect-metadata?
I'm currently learning TypeScript with Node. Reading about TypeORM, I saw that the reflect-metadata package is needed for TypeORM to work. What is the reason for this package being needed?
Erik
- 159
- 2
- 11
10
votes
3 answers
Angular4 core.es5.js Uncaught reflect-metadata shim is required when using class decorators
After upgrading my pre-existing project to Angular 4 and Angular/CLI 1.0 I'm getting this error:
core.es5.js:354 Uncaught reflect-metadata shim is required when using class decorators
I've compared my project to a fresh ng new and they appear alike…
Mikeumus
- 3,570
- 9
- 40
- 65
9
votes
1 answer
How to access class metadata from method decorator
I'm having two decorators. A class decorator and a method decorator.
The class decorator defines metadata which I want to access in the method decorator.
ClassDecorator:
function ClassDecorator(topic?: string): ClassDecorator {
return (target)…
tmuecksch
- 6,222
- 6
- 40
- 61
8
votes
2 answers
Get return type with reflect-metadata , when return type is Promise of something
When function return type is Promise , how can i get it with reflection?
If i just do
Reflect.getMetadata("design:returntype", target, key)
it's return just Promise, so there is a way to know that is Promise of…
yantrab
- 2,482
- 4
- 31
- 52
7
votes
2 answers
Why can't reflect-metadata be used in vite
import "reflect-metadata"
function validate(target: any) {
let paramtypes = Reflect.getMetadata("design:paramtypes", target);
console.log(paramtypes); // undefined
}
@validate
class Log {
constructor(public readonly xx: string) {}
}
Hit me…
januw a
- 2,056
- 5
- 18
- 39
7
votes
1 answer
get List of reflect-metadata decorated fields of class
I'm using reflect-metadata with typescript. I composed my own property decorator and it's called Field. How to get list of fields/properties, which are decorated by Field, of any type. For example: I want to get ProductID, ProductName field with…
dvl Batdelger
- 151
- 1
- 11
6
votes
1 answer
Typescript decorators + Reflect metadata
I'm using a property decorator Field which pushes its' key to a fields Reflect metadata property:
export function Field(): PropertyDecorator {
return (target, key) => {
const fields = Reflect.getMetadata('fields', target) || [];
…
nomadoda
- 4,561
- 3
- 30
- 45
6
votes
2 answers
@Reflect.metadata generates error TS1238: Unable to resolve signature of class decorator when called as an expression
I tried to apply the @Reflect.metadata decorator to a TypeScript class, following the example on lines 82-84 of reflect-metadata.d.ts:
///
Michael Liu
- 52,147
- 13
- 117
- 150
5
votes
3 answers
After typescript update 2.3.4 => 2.4.2 i get compilation error "Cannot find type definition file for 'reflect-metadata'."
I have a React / Mobex application written in TypeScript, built by Webpack 1. After updating TypeScript version from 2.3.4 to 2.4.2 i get an error
ERROR in C:\myproject\tsconfig.json
error TS2688: Cannot find type definition file for…
Ivan Koshelev
- 3,830
- 2
- 30
- 50
5
votes
1 answer
Why is reflect-metadata only working when using a decorator?
Without decorators the metadata is lost - but why?
const Baz = () : ClassDecorator => {
return target => {}
}
class Bar {}
@Baz()
class Foo {
constructor(bar: Bar) {}
}
console.log(Reflect.getMetadata('design:paramtypes', Foo));
This returns…
nehalist
- 1,434
- 18
- 45
4
votes
0 answers
Typescript: How to get metadata types info about public fields in class decorator
I'm using reflect-metadata lib and Typescript decorators.
I have this class for example (real one will have much more fields):
class Message {
@FieldTyping
text: string;
@FieldTyping
code: number;
constructor(text: string,…
FantaZ
- 49
- 1
- 2
