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[英]expression of type 'string' can't be used to index type 'Object'. No index signature with a parameter of type 'string' was found on type 'Object'
[英]No index signature with a parameter of type 'string' was found on type 'typeof Object'
我做了一個類似 enum 的課程: https : //stackoverflow.com/a/51398471
export default class Juice
{
[key: string]: any;
static APPLE = new Juice('APPLE', 'Apple juice');
static ORANGE = new Juice('ORANGE', 'Orange juice');
private constructor(private key:string, public readonly text:string) {
};
}
當我使用我定義的密鑰訪問時,它工作正常,但是當我嘗試像這樣動態訪問時它失敗了:
console.log(Juice.APPLE); //works fine
console.log(Juice['APPLE']); //works fine
const key = 'APPLE'; //works fine
console.log(Juice[key]); //works fine
console.log(Object.keys(Juice).map((key:string) => Juice[key])); // error!
錯誤是:
TypeScript error in `path`
Element implicitly has an 'any' type because expression of type 'string' can't be used to index type 'typeof Juice'.
No index signature with a parameter of type 'string' was found on type 'typeof Juice'. TS7053
有沒有人幫助我錯誤的原因和解決方案?
請幫忙,謝謝。
我在類中添加了索引簽名,但沒有幫助
[key: string]: any;
export default class Juice
{
[key: string]: any;
static APPLE = new Juice('APPLE', 'Apple juice');
static ORANGE = new Juice('ORANGE', 'Orange juice');
private constructor(private key:string, public readonly text:string) {
};
}
獲取enum
類的列表。
問題似乎是使用Object.keys
因為它總是遍歷字符串列表與作為對象鍵的字符串列表。 如果你想獲得一個對象的所有值,我會改用Object.values
。 但是,這會導致問題,因為構造函數也將作為值(原型)返回,這將導致其他類型問題。
我建議將您的靜態果汁作為一個單獨的對象,您可以在需要時參考。 例子:
class Juice {
constructor(private key: string, public readonly text: string) {}
}
const juices = {
APPLE: new Juice('APPLE', 'Apple juice'),
ORANGE: new Juice('ORANGE', 'Orange juice')
};
export default juices;
console.log(Object.values(Juice));
const test: keyof typeof juices = 'APPLE';
console.log(juices[test]);
我希望這可以幫到你。
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