你有两个选择:
- 在类本身中定义手表
// first you need to install vue-property-decorators with npm i -S vue-property-decorator
// This library has a lot of useful decorators. You can read more about it here: https://github.com/kaorun343/vue-property-decorator
import { Vue, Component, Watch } from 'vue-property-decorator'
@Component
export default class Info extends Vue {
@Watch('firstMesh')
public watchFirstMesh(newValue) {
// ... do whatever you need to do with the newValue here
}
@Watch('secondMesh')
public watchSecondMesh(newValue) {
// ... do whatever you need to do with the newValue here
}
}
- 在 @Component 的选项部分定义监视和方法
@Component({
watch: {
firstMesh(newMesh) {
if (newMesh === undefined) this.clearInfo(1); // this produces the errors
else this.showMeshInfo(newMesh, 1);
},
secondMesh(newMesh) {
if (newMesh === undefined) this.clearInfo(2);
else this.showMeshInfo(newMesh, 2);
},
},
methods: {
clearInfo(whichMesh : number) {
...
},
showMeshInfo(mesh : any, index : number) {
....
}
}
})
export default class Info extends Vue {
// Now you need to tell to typescript that there will be a method inside this class called clearInfo and showMeshInfo
public clearInfo!: (wichMesh: number) => void;
public showMeshInfo!: (mesh: any, index: number) => void;
}
解释
可以在我留下的链接上阅读解释
由于您在装饰器中定义选项,因此@Component({...})
这将在类将被实例化的上下文中可用。Typescript 不知道究竟有什么可用(我们希望它那么聪明)。你必须告诉它,这就是我们拥有这个public clearInfo!: (wichMesh: number) => void;
角色的原因。如果你不知道这个语法是什么意思,我会用简短的语言解释并在最后留下一个链接:
public clearInfo!: (wichMesh: number) => void;
the ! part is called the non-null assertion operator. It is a way to tell the compiler "this expression cannot be null or undefined here, so don't complain about the possibility of it being null or undefined."
The (wichMesh: number) => void; is the function signature. Basically it says: this will be a function that receives as the first argument a number (whichMesh) and returns void (=> void)
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