'new'表达式,其目标在TypeScript中缺少构造签名 [英] 'new' expression, whose target lacks a construct signature in TypeScript
问题描述
我们有以下 TestComponent.ts
TypeScript类:
We have the following TestComponent.ts
TypeScript class:
01: import TestVectorLayer from './TestVectorLayer'
02:
03: export class TestComponent implements OnInit {
04: private foo: any;
05:
06: constructor() { }
07:
08: const layer = new TestVectorLayer("foo");
09: }
以下 TestVectorLayer.ts
功能:
请记住,OpenLayer的3正在使用Google Closure库,这就是为什么 TestVectorLayer
不是TypeScript类。
Keep in mind that OpenLayer's 3 is using the Google Closure Library, that's why TestVectorLayer
is not a TypeScript class.
01: declare let ol: any;
02:
03: const TestVectorLayer = function (layerName: string) {
04: ...
05: console.log(layerName);
06:
07: ol.layer.Image.call(this, opts);
08: }
09:
10: ol.inherits(TestVectorLayer as any, ol.layer.Image as any);
11:
12: export default TestVectorLayer;
我们收到以下错误:
Error on Line 08 in TestComponent.ts class:
[ts]'new'表达式,其目标缺少构造签名,隐式具有any类型。
import TestVectorLayer
[ts] 'new' expression, whose target lacks a construct signature, implicitly has an 'any' type. import TestVectorLayer
TypeScript的 package.json
版本:
The package.json
versions of TypeScript:
devDependencies:
devDependencies:
"typescript": "~2.2.1"
推荐答案
以下是问题的简化:
const TestVectorLayer = function(layerName: string) {
};
const layer = new TestVectorLayer("");
发生错误是因为 TestVectorLayer
没有' t有一个新签名,因此 layer
隐式输入为 any
。错误 - noImplicitAny
。
The error is happening because TestVectorLayer
doesn't have a new signature, so layer
is implicitly typed as any
. That errors with --noImplicitAny
.
你可以通过切换到一个类来解决这个问题,但在你的情况下这个看起来有点复杂,因为继承是由底层框架完成的。因此,你必须做一些更复杂的事情并且它不理想:
You can fix this by switching to a class, but in your case this seems a bit more complicated because the inheritance is done by the underlying framework. Because of that, you will have to do something a bit more complicated and it's not ideal:
interface TestVectorLayer {
// members of your "class" go here
}
const TestVectorLayer = function (this: TestVectorLayer, layerName: string) {
// ...
console.log(layerName);
ol.layer.Image.call(this, opts);
} as any as { new (layerName: string): TestVectorLayer; };
ol.inherits(TestVectorLayer, ol.layer.Image);
export default TestVectorLayer;
然后在包含 TestComponent
的文件中:
const layer = new TestVectorLayer(layerName); // no more compile error
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