feat: add fallback for window width (#45)

README.md

@@ -10,9 +10,7 @@ easily create complex multi-column command-line-interfaces.
 ## Example
 
 ```js
-var ui = require('cliui')({
-  width: 80
-})
+var ui = require('cliui')()
 
 ui.div('Usage: $0 [command] [options]')
 
@@ -88,6 +86,7 @@ cliui = require('cliui')
 ### cliui({width: integer})
 
 Specify the maximum width of the UI being generated.
+If no width is provided, cliui will try to get the current window's width and use it, and if that doesn't work, width will be set to `80`.
 
 ### cliui({wrap: boolean})
 

index.js

@@ -282,6 +282,10 @@ function _minWidth (col) {
   return minWidth
 }
 
+function getWindowWidth () {
+  if (typeof process === 'object' && process.stdout && process.stdout.columns) return process.stdout.columns
+}
+
 function alignRight (str, width) {
   str = str.trim()
   var padding = ''
@@ -310,7 +314,7 @@ module.exports = function (opts) {
   opts = opts || {}
 
   return new UI({
-    width: (opts || {}).width || 80,
+    width: (opts || {}).width || getWindowWidth() || 80,
     wrap: typeof opts.wrap === 'boolean' ? opts.wrap : true
   })
 }