如何在Node.js中無限讀取

Question

while(1){ 
    rl.question("Command: ",function(answer){ 
    console.log(answer); 
    }) 
} 

剛剛嘗試過這段代碼，但是一個接一個地輸入，它會閃爍「Command：」行。我知道node.js是非阻塞的，但我不知道如何解決這個問題。

Answer 1

var readline = require('readline'); 
var log = console.log; 

var rl = readline.createInterface({ 
    input: process.stdin, 
    output: process.stdout 
}); 

var recursiveAsyncReadLine = function() { 
    rl.question('Command: ', function (answer) { 
    if (answer == 'exit') //we need some base case, for recursion 
     return rl.close(); //closing RL and returning from function. 
    log('Got it! Your answer was: "', answer, '"'); 
    recursiveAsyncReadLine(); //Calling this function again to ask new question 
    }); 
}; 

recursiveAsyncReadLine(); //we have to actually start our recursion somehow 

關鍵是不要使用同步環。處理答案後我們應該詢問下一個rl.question。遞歸是要走的路。我們定義函數詢問問題並處理答案，然後在答覆處理後從內部調用它。這種方式我們從頭開始，就像常規循環一樣。但循環不關心ansyc代碼，而我們的實現關心。

Answer 2

另一種選擇，通過Node.js的文檔，是使用events：

var readline = require('readline'), 
    rl = readline.createInterface(process.stdin, process.stdout); 

rl.setPrompt('OHAI> '); 
rl.prompt(); 

rl.on('line', function(line) { 
    switch(line.trim()) { 
     case 'hello': 
      console.log('world!'); 
      break; 
     default: 
      console.log('Say what? I might have heard `' + line.trim() + '`'); 
     break; 
    } 
    rl.prompt(); 
}).on('close', function() { 
    console.log('Have a great day!'); 
    process.exit(0); 
});