为什么我得到“TypeError：对象不是一个函数”运行这个例子node.js代码？
为什么运行下面显示的代码时出现错误？ （在Coursera的斯坦福“启动工程”课程中的作业之一： https ：//class.coursera.org/startup-001/quiz/attempt ？ quiz_id = 149）
该课程于2013年6月份开始运行，因此可能是已经更新了节点或csv，可能会破坏脚本？ 作业不是固定剧本，所以这个问题不是“作弊”，而且课程目前还没有运行。
所以，环境是：Ubuntu 14.04（kernel 3-13-0-29-generic），node v0.11.13，npm v1.4.9
我有npm install在主目录中npm install 'd csv，accounting util和restler，脚本也在那里。
这让我完全难倒…. 🙁
错误信息：
[ubuntu@ip-xxx-xxx-xxx-xxx:~]$node market-research.js Invoked at command line. Wrote market-research.csv Symbol Name Market Cap Previous Close Price P/E Ratio Shares EPS Earnings /home/ubuntu/market-research.js:47 csv() ^ TypeError: object is not a function at csv2console (/home/ubuntu/market-research.js:47:5) at Request.response2console (/home/ubuntu/market-research.js:65:13) at Request.EventEmitter.emit (events.js:110:17) at Request.mixin._fireSuccess (/home/ubuntu/node_modules/restler/lib/restler.js:226:10) at /home/ubuntu/node_modules/restler/lib/restler.js:158:20 at IncomingMessage.parsers.auto (/home/ubuntu/node_modules/restler/lib/restler.js:394:7) at Request.mixin._encode (/home/ubuntu/node_modules/restler/lib/restler.js:195:29) at /home/ubuntu/node_modules/restler/lib/restler.js:154:16 at Request.mixin._decode (/home/ubuntu/node_modules/restler/lib/restler.js:170:7) at IncomingMessage.<anonymous> (/home/ubuntu/node_modules/restler/lib/restler.js:147:14) [ubuntu@ip-xxx-xxx-xxx-xxx:~]$
码：
#!/usr/bin/env node /* Use the Yahoo Finance CSV API to do some basic market research calculations. - Background: http://greenido.wordpress.com/2009/12/22/yahoo-finance-hidden-api/ - Example URL: http://finance.yahoo.com/d/quotes.csv?s=GOOG+FB+AAPL&f=snj1pr s: Symbol n: Name j1: Market Capitalization (in billions) p: Price-per-share (at previous close) r: Price to Earnings Ratio Further references. - https://github.com/danwrong/restler - https://github.com/wdavidw/node-csv - http://josscrowcroft.github.io/accounting.js - http://stackoverflow.com/questions/4981891/node-js-equivalent-of-pythons-if-name-main - http://nodejs.org/docs/latest/api/util.html#util_util_format_format */ var util = require('util'); var fs = require('fs'); var rest = require('restler'); var csv = require('csv'); var accounting = require('accounting'); var CSVFILE_DEFAULT = "market-research.csv"; var SYMBOLS_DEFAULT = ["GOOG", "FB", "AAPL", "YHOO", "MSFT", "LNKD", "CRM"]; var COLUMNS_DEFAULT = 'snj1pr'; // http://greenido.wordpress.com/2009/12/22/yahoo-finance-hidden-api var HEADERS_DEFAULT = ["Symbol", "Name", "Market Cap", "Previous Close Price", "P/E Ratio", "Shares", "EPS", "Earnings"]; var financeurl = function(symbols, columns) { return util.format( 'http://finance.yahoo.com/d/quotes.csv?s=%s&f=%s', symbols.join('+'), columns); }; var marketCapFloat = function(marketCapString) { return parseFloat(marketCapString.split('B')[0]) * 1e9; }; var csv2console = function(csvfile, headers) { console.log(headers.join("\t")); csv() .from.path(csvfile) .on('record', function(row, index) { var shares = Math.round(marketCapFloat(row[2])/row[3], 0); var eps = (row[3]/row[4]).toFixed(3); var earnings = accounting.formatMoney(eps * shares); outrow = row.concat([shares, eps, earnings]); console.log(outrow.join("\t")); }); }; var buildfn = function(csvfile, headers) { var response2console = function(result, response) { if (result instanceof Error) { console.error('Error: ' + util.format(response.message)); } else { console.error("Wrote %s", csvfile); fs.writeFileSync(csvfile, result); csv2console(csvfile, headers); } }; return response2console; }; var marketResearch = function(symbols, columns, csvfile, headers) { symbols = symbols || SYMBOLS_DEFAULT; columns = columns || COLUMNS_DEFAULT; csvfile = csvfile || CSVFILE_DEFAULT; headers = headers || HEADERS_DEFAULT; var apiurl = financeurl(symbols, columns); var response2console = buildfn(csvfile, headers); rest.get(apiurl).on('complete', response2console); }; if(require.main == module) { console.error('Invoked at command line.'); var symbols = process.argv; if(symbols.length > 2) { symbols = symbols.slice(2, symbols.length); } else { symbols = undefined; }; marketResearch(symbols); } else { console.error('Invoked via library call'); } exports.marketResearch = marketResearch;
由脚本创build的market-research.csv的内容：
"GOOG","Google Inc.",386.6B,569.20,29.49 "FB","Facebook, Inc.",194.5B,73.855,78.49 "AAPL","Apple Inc.",613.8B,102.25,16.49 "YHOO","Yahoo! Inc.",38.302B,38.31,33.11 "MSFT","Microsoft Corpora",374.3B,44.88,17.06 "LNKD","LinkedIn Corporat",27.747B,223.26,N/A "CRM","Salesforce.com In",36.577B,58.29,N/A
Quantas 94重，感谢提示。
12个月前，node-csv的版本是0.2，但现在是0.4，API已经改变了。
我现在写了csv-console函数，如下所示：
// part of file market-script.js // edited by Jeff Moye (Moyesoft) // no attribution in the original file var csv2console = function(csvfile, headers) { console.log(headers.join("\t")); var parser = csv.parse(); //create the parser parser.on('readable', function(){ //the 'record' event no longer exists // so instead we write a handler for the // 'readable' event while(record = parser.read()){ // and read() each record in a loop var shares = Math.round(marketCapFloat(record[2])/record[3], 0); var eps = (record[3]/record[4]).toFixed(3); var earnings = accounting.formatMoney(eps * shares); outrow = record.concat([shares, eps, earnings]); console.log(outrow.join("\t")); } }); parser.on('error', function(err){ // we may as well have an error handler console.log(err.message); }); fs.createReadStream(csvfile).pipe(parser); //open file as a stream and pipe it to the parser };