timer._repeat不是函數嗎？

Question

節點v4.2.6

我有一個小節目：

var chokidar = require('chokidar'); 
var _ = require('lodash'); 
var q = require('q'); 
var fs = require('fs'); 
var faker = require('faker'); 
var file = 'testfile.txt'; 
var pending = ''; 
var writer; 

fs.open(file,'w+',function(){ 
    writer = fs.createWriteStream(file); 

    writer.on('error',function(err){ 
     console.log(err); 
    }); 

    writer.on('drain',rewrite); 

    var timer = setInterval(write(),100); 
}); 

function write(){ 
    var data = faker.Helpers.createCard(); 
    console.log('attempting to write ' + Buffer.byteLength(data,'utf8') + ' bytes'); 
    var ok = writer.write(data.toString()); 
    if(!ok){ 
     console.log('buffer full, saving in memory'); 
     pending += data; 
    }else{ 
     console.log('written'); 
    } 
} 

function rewrite(){ 
    console.log('buffer empty, writing ' + Buffer.byteLength(data,'utf8') + ' bytes from memory'); 
    var ok = writer.write(pending); 
    if(!ok){ 
     console.log('buffer full again. Saving in memory again'); 
     pending += data; 
    } 
} 

之後將其寫入文件中的前幾個字節，它的錯誤了與：

timers.js:275 
    timer._repeat(); 
     ^

TypeError: timer._repeat is not a function 
    at wrapper [as _onTimeout] (timers.js:275:11) 
    at Timer.listOnTimeout (timers.js:92:15) 

什麼錯和我該如何糾正它？

Answer 1

此：

var timer = setInterval(write(),100); 

正在通過結果的write()作爲函數每100毫秒被調用。 write()不返回一個函數（undefined隱式返回），所以你得到TypeError。相反，通過函數本身：

var timer = setInterval(write,100);