Calling functions from `coffee` executable

Question

Forgive the noob question, but why is it that I can't call (almost) any standard functions from the coffee REPL (or from files written and run within TextMate, for that matter)?

Variable assignment works, functions don't.

Examples:

coffee> string = "string"
'string'
coffee> list = [1,2,3]
[ 1, 2, 3 ]
coffee> num = 42
42
coffee> opposite = true
true
coffee> num = -42 if opposite
-42

but

coffee> alert "Hello, World"
ReferenceError: alert is not defined
    at repl:1:5
    at REPLServer.replDefaults.eval (/usr/local/lib/node_modules/coffee-script/lib/coffee-script/repl.js:33:28)
    at repl.js:239:12
    at Interface.<anonymous> (/usr/local/lib/node_modules/coffee-script/lib/coffee-script/repl.js:62:9)
    at Interface.EventEmitter.emit (events.js:117:20)
    at Interface._onLine (readline.js:202:10)
    at Interface._line (readline.js:531:8)
    at Interface._ttyWrite (readline.js:760:14)
    at ReadStream.onkeypress (readline.js:99:10)
    at ReadStream.EventEmitter.emit (events.js:117:20)

and

coffee> print "Hello"
ReferenceError: print is not defined
    at repl:1:5
    at REPLServer.replDefaults.eval (/usr/local/lib/node_modules/coffee-script/lib/coffee-script/repl.js:33:28)
    at repl.js:239:12
    at Interface.<anonymous> (/usr/local/lib/node_modules/coffee-script/lib/coffee-script/repl.js:62:9)
    at Interface.EventEmitter.emit (events.js:117:20)
    at Interface._onLine (readline.js:202:10)
    at Interface._line (readline.js:531:8)
    at Interface._ttyWrite (readline.js:760:14)
    at ReadStream.onkeypress (readline.js:99:10)
    at ReadStream.EventEmitter.emit (events.js:117:20)

What really gets me is:

coffee> console.log "Help!"
Help!
undefined

I have Node installed via Homebrew and CoffeeScript installed (globally) via npm.

Answer 1

alert is not a feature of javascript. It's part of the API the browser exposes to JavaScript. And coffee at the command line on you computer is just a thin wrapper around node.js that translated coffee script into javascript to be interpreted by node. node.js does not provide an alert function. Nor does it provide a global print function.

Both node, and the browser, do provide a console object globally. So console.log works the same.

Brush up on the node docs to learn what function node exposes. And rememebr that just because it works in a browser does not mean it will work in node.

Answer 2

alert and print are not native node.js functions

If you want to get started at the command line with coffee without making changes to example code snippets try the following two assignments at the prompt before running your code.

print = console.log
alert = console.log

Here is a small Hello World function to get you started:-

coffee> hello = (word) -> console.log "Hello " + word
coffee> hello "World"
Hello World

Answer 3

before you use 'alert' command

1. must install 'alert-node' lib
2. require 'alert-node' to your script

follow in this link -> Alert function not working in coffeescript

npm install alert-node

alert = require('alert-node')