原型字符串以打字稿

Question

的JavaScript字符串中打字稿2.0.3以下的原型方法：

interface String { 
    splice(start: number, delCount: number, newSubStr: string): string; 
} 

String.prototype.splice = function(idx: number, rem: number, str: string): string { 
    return this.slice(0, idx) + str + this.slice(idx + Math.abs(rem)); 
}; 

引發錯誤：

error TS2339: Property 'splice' does not exist on type 'String'.

儘管我的界面。它似乎在操場上運行良好。我只在該文件上運行tsc，沒有選項。爲什麼這不起作用？

Answer 1

It seems to work fine in the playground.

那是因爲你可能在你的文件的import/export。修復：

declare global { 
    interface String { 
     splice(start: number, delCount: number, newSubStr: string): string; 
    } 
} 

String.prototype.splice = function(idx: number, rem: number, str: string): string { 
    return this.slice(0, idx) + str + this.slice(idx + Math.abs(rem)); 
}; 

更多

這是這裏介紹：https://basarat.gitbooks.io/typescript/content/docs/types/lib.d.ts.html#modifying-native-types