Why am I getting "TypeError: object is not a function" running this example node.js code?

Question

Why does an error occur when running the code shown below? (It was used in one of the homework in the Stanford Startup course on Coursera: https://class.coursera.org/startup-001/quiz/attempt?quiz_id=149 )

The course took place in June-September 2013, so there may have been node or csv updates that broke the script, maybe? The homework is not related to fixing the script, so this question is not a cheat, and the course is not currently running.

So, Wednesday: Ubuntu 14.04 (kernel 3-13-0-29-shared), node v0.11.13, npm v1.4.9

And I have npm install 'd csv, account and restler in the home directory, as well as a script.

It completely surpassed me ....: - (

error message:

 [ ubuntu@ip-xxx-xxx -xxx-xxx:~]$node market-research.js Invoked at command line. Wrote market-research.csv Symbol Name Market Cap Previous Close Price P/E Ratio Shares EPS Earnings /home/ubuntu/market-research.js:47 csv() ^ TypeError: object is not a function at csv2console (/home/ubuntu/market-research.js:47:5) at Request.response2console (/home/ubuntu/market-research.js:65:13) at Request.EventEmitter.emit (events.js:110:17) at Request.mixin._fireSuccess (/home/ubuntu/node_modules/restler/lib/restler.js:226:10) at /home/ubuntu/node_modules/restler/lib/restler.js:158:20 at IncomingMessage.parsers.auto (/home/ubuntu/node_modules/restler/lib/restler.js:394:7) at Request.mixin._encode (/home/ubuntu/node_modules/restler/lib/restler.js:195:29) at /home/ubuntu/node_modules/restler/lib/restler.js:154:16 at Request.mixin._decode (/home/ubuntu/node_modules/restler/lib/restler.js:170:7) at IncomingMessage.<anonymous> (/home/ubuntu/node_modules/restler/lib/restler.js:147:14) [ ubuntu@ip-xxx-xxx-xxx-xxx :~]$ 

the code:

  #!/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.imtqy.com/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; 

contents of market-research.csv generated by the script:

  "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 

Answer 1

Quantas 94 Heavy, thanks for the tip.

12 months ago, node -csv was in version 0.2, but now it is 0.4 and the API has changed.

Now I wrote the csv-console function as follows:

 // 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 };