TypeScript readline.createInterface抛出异常
问题描述:
我正在尝试创建一个电子应用程序。在main.ts中,我构建了我认为是相当简单的类(下面),但构造函数不会运行。对readline.createInterface(inputStream)的调用失败。看起来运行时并不认为调用fs.createReadStream返回的变量有一个名为'on'的函数。TypeScript readline.createInterface抛出异常
唯一的例外是
Uncaught Exception:
TypeError: Cannot read property 'on' of undefined
at new Interface (readline.js:142:10)
at Object.exports.createInterface (readline.js:28:10)
at new FileMonitor (/Users/mikedice/code/electron-rm/app/FileMonitor.js:13:38)
at App.Main.onReady (/Users/mikedice/code/electron-rm/app/Main.js:27:23)
at emitTwo (events.js:111:20)
at App.emit (events.js:191:7)
这是生成它的代码块。
import readline = require("readline");
import fs = require("fs");
export class FileMonitor
{
constructor(public filePath:string){
if (!fs.existsSync(filePath)){
console.log(`file does not exist at path ${filePath}`);
return;
}
var inputStream = fs.createReadStream(filePath);
var readInterface = readline.createInterface(inputStream);
readInterface.on('line', (val)=>{
// when new lines arrive we can publish an event to listeners
console.log(val);
});
}
}
我认为,问题是,在文件/Users/mikedice/code/electron-rm/node_modules/@types/node/index.d.ts的fs.createReadStream返回ReadStream对象和相同的文件readline.createInterface期望NodeJS.ReadableStream和TypeScript将这两种类型视为不同,即使运行时期望它们是相同的东西。我不确定这个问题的解决方案是什么,总的来说,这种类型的问题。看起来这种语言的类型系统与运行时不一致,但不知道为什么运行时无法解决代码执行时的问题。有什么建议么?
export function createReadStream(path: string | Buffer, options?: {
flags?: string;
encoding?: string;
fd?: number;
mode?: number;
autoClose?: boolean;
start?: number;
end?: number;
}): ReadStream;
export function createInterface(input: NodeJS.ReadableStream,
output?: NodeJS.WritableStream,
completer?: Completer | AsyncCompleter,
terminal?: boolean): ReadLine;
答
您需要修改readline.createInterface()
选项调用传递对象与物业input.readline
。 createInterface()
需要分配输入和/或输出流的对象。
readline.createInterface({input: inputStream});
行了。您的建议工作,也工作: readline.createInterface(inputStream,null,null,null); – MikeDice
@MikeDice如果此答案解决了您的问题,请考虑将其标记为已通过点击绿色复选标记。 – Motti