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Decorator

警告
  • 动态类不支持 Decorator 语法, 依赖代码生成
type Decorator = (value: Input, context: {
kind: string;
name: string | symbol;
access: {
get?(): unknown;
set?(value: unknown): void;
};
private?: boolean;
static?: boolean;
addInitializer?(initializer: () => void): void;
// TS 5.2
metadata?: Record<string | number | symbol, unknown>;
}) => Output | void;

type ClassMethodDecorator = (value: Function, context: {
kind: "method";
name: string | symbol;
access: { get(): unknown };
static: boolean;
private: boolean;
addInitializer(initializer: () => void): void;
}) => Function | void;

type ClassGetterDecorator = (value: Function, context: {
kind: "getter";
name: string | symbol;
access: { get(): unknown };
static: boolean;
private: boolean;
addInitializer(initializer: () => void): void;
}) => Function | void;

type ClassSetterDecorator = (value: Function, context: {
kind: "setter";
name: string | symbol;
access: { set(value: unknown): void };
static: boolean;
private: boolean;
addInitializer(initializer: () => void): void;
}) => Function | void;

type ClassFieldDecorator = (value: undefined, context: {
kind: "field";
name: string | symbol;
access: { get(): unknown, set(value: unknown): void };
static: boolean;
private: boolean;
}) => (initialValue: unknown) => unknown | void;

type ClassDecorator = (value: Function, context: {
kind: "class";
name: string | undefined;
addInitializer(initializer: () => void): void;
}) => Function | void;

type ClassAutoAccessorDecorator = (
value: {
get: () => unknown;
set: (value: unknown) => void;
},
context: {
kind: "accessor";
name: string | symbol;
access: { get(): unknown, set(value: unknown): void };
static: boolean;
private: boolean;
addInitializer(initializer: () => void): void;
}
) => {
get?: () => unknown;
set?: (value: unknown) => void;
init?: (initialValue: unknown) => unknown;
} | void;

Typescript legacy

declare type ClassDecorator = <TFunction extends Function>(target: TFunction) => TFunction | void;
declare type PropertyDecorator = (target: Object, propertyKey: string | symbol) => void;
declare type MethodDecorator = <T>(
target: Object,
propertyKey: string | symbol,
descriptor: TypedPropertyDescriptor<T>,
) => TypedPropertyDescriptor<T> | void;
declare type ParameterDecorator = (
target: Object,
propertyKey: string | symbol | undefined,
parameterIndex: number,
) => void;
const ExposeService = (): ClassDecorator => (target) => target;
const ExposeMethod = (): MethodDecorator => (target) => target;
const ExposeField = (): PropertyDecorator => (target) => target;

@ExposeService()
class MyService {
@ExposeField()
url: string = 'https://wener.me';

@ExposeMethod()
hello(name: string): string | undefined {
return '';
}
}
'use strict';
var __decorate =
(this && this.__decorate) ||
function (decorators, target, key, desc) {
var c = arguments.length,
r = c < 3 ? target : desc === null ? (desc = Object.getOwnPropertyDescriptor(target, key)) : desc,
d;
if (typeof Reflect === 'object' && typeof Reflect.decorate === 'function')
r = Reflect.decorate(decorators, target, key, desc);
else
for (var i = decorators.length - 1; i >= 0; i--)
if ((d = decorators[i])) r = (c < 3 ? d(r) : c > 3 ? d(target, key, r) : d(target, key)) || r;
return c > 3 && r && Object.defineProperty(target, key, r), r;
};
var __metadata =
(this && this.__metadata) ||
function (k, v) {
if (typeof Reflect === 'object' && typeof Reflect.metadata === 'function') return Reflect.metadata(k, v);
};
const ExposeService = () => (target) => target;
const ExposeMethod = () => (target) => target;
const ExposeField = () => (target) => target;
let MyService = class MyService {
constructor() {
this.url = 'https://wener.me';
}
hello(name) {
return '';
}
};
__decorate([ExposeField(), __metadata('design:type', String)], MyService.prototype, 'url', void 0);
__decorate(
[
ExposeMethod(),
__metadata('design:type', Function),
__metadata('design:paramtypes', [String]),
__metadata('design:returntype', Object),
],
MyService.prototype,
'hello',
null,
);
MyService = __decorate([ExposeService()], MyService);

Typescript next

const ExposeService = () => (value: any, ctx: ClassDecoratorContext) => {};
const ExposeMethod = () => (value: any, ctx: ClassMethodDecoratorContext) => {};
const ExposeField = () => (value: any, ctx: ClassFieldDecoratorContext) => {};

@ExposeService()
class MyService {
@ExposeField()
url: string = 'https://wener.me';

@ExposeMethod()
hello(name: string): string | undefined {
return '';
}
}
'use strict';
var __esDecorate =
(this && this.__esDecorate) ||
function (ctor, descriptorIn, decorators, contextIn, initializers, extraInitializers) {
function accept(f) {
if (f !== void 0 && typeof f !== 'function') throw new TypeError('Function expected');
return f;
}
var kind = contextIn.kind,
key = kind === 'getter' ? 'get' : kind === 'setter' ? 'set' : 'value';
var target = !descriptorIn && ctor ? (contextIn['static'] ? ctor : ctor.prototype) : null;
var descriptor = descriptorIn || (target ? Object.getOwnPropertyDescriptor(target, contextIn.name) : {});
var _,
done = false;
for (var i = decorators.length - 1; i >= 0; i--) {
var context = {};
for (var p in contextIn) context[p] = p === 'access' ? {} : contextIn[p];
for (var p in contextIn.access) context.access[p] = contextIn.access[p];
context.addInitializer = function (f) {
if (done) throw new TypeError('Cannot add initializers after decoration has completed');
extraInitializers.push(accept(f || null));
};
var result = (0, decorators[i])(
kind === 'accessor' ? { get: descriptor.get, set: descriptor.set } : descriptor[key],
context,
);
if (kind === 'accessor') {
if (result === void 0) continue;
if (result === null || typeof result !== 'object') throw new TypeError('Object expected');
if ((_ = accept(result.get))) descriptor.get = _;
if ((_ = accept(result.set))) descriptor.set = _;
if ((_ = accept(result.init))) initializers.unshift(_);
} else if ((_ = accept(result))) {
if (kind === 'field') initializers.unshift(_);
else descriptor[key] = _;
}
}
if (target) Object.defineProperty(target, contextIn.name, descriptor);
done = true;
};
var __runInitializers =
(this && this.__runInitializers) ||
function (thisArg, initializers, value) {
var useValue = arguments.length > 2;
for (var i = 0; i < initializers.length; i++) {
value = useValue ? initializers[i].call(thisArg, value) : initializers[i].call(thisArg);
}
return useValue ? value : void 0;
};
const ExposeService = () => (value, ctx) => {};
const ExposeMethod = () => (value, ctx) => {};
const ExposeField = () => (value, ctx) => {};
let MyService = (() => {
let _classDecorators = [ExposeService()];
let _classDescriptor;
let _classExtraInitializers = [];
let _classThis;
let _instanceExtraInitializers = [];
let _url_decorators;
let _url_initializers = [];
let _hello_decorators;
var MyService = class {
static {
_classThis = this;
}
constructor() {
this.url =
(__runInitializers(this, _instanceExtraInitializers),
__runInitializers(this, _url_initializers, 'https://wener.me'));
}
static {
const _metadata = typeof Symbol === 'function' && Symbol.metadata ? Object.create(null) : void 0;
_url_decorators = [ExposeField()];
_hello_decorators = [ExposeMethod()];
__esDecorate(
this,
null,
_hello_decorators,
{
kind: 'method',
name: 'hello',
static: false,
private: false,
access: { has: (obj) => 'hello' in obj, get: (obj) => obj.hello },
metadata: _metadata,
},
null,
_instanceExtraInitializers,
);
__esDecorate(
null,
null,
_url_decorators,
{
kind: 'field',
name: 'url',
static: false,
private: false,
access: {
has: (obj) => 'url' in obj,
get: (obj) => obj.url,
set: (obj, value) => {
obj.url = value;
},
},
metadata: _metadata,
},
_url_initializers,
_instanceExtraInitializers,
);
__esDecorate(
null,
(_classDescriptor = { value: _classThis }),
_classDecorators,
{ kind: 'class', name: _classThis.name, metadata: _metadata },
null,
_classExtraInitializers,
);
MyService = _classThis = _classDescriptor.value;
if (_metadata)
Object.defineProperty(_classThis, Symbol.metadata, {
enumerable: true,
configurable: true,
writable: true,
value: _metadata,
});
__runInitializers(_classThis, _classExtraInitializers);
}
hello(name) {
return '';
}
};
return (MyService = _classThis);
})();