Merge pull request #16 from mapbox/positional-mbtiles-param

Positional mbtiles param

cli.js

@@ -3,20 +3,28 @@
 var argv = require('minimist')(process.argv.slice(2));
 var path = require('path');
 var open = require('open');
+var fs = require('fs');
 
+argv.mbtiles = argv.mbtiles || argv._[0];
 if (!argv.mbtiles) {
     console.log(usage());
     process.exit(1);
 }
 
 argv.basemap = argv.basemap || argv.base || argv.map || 'dark';
 
+try {
+    fs.statSync(argv.mbtiles).isFile();
+} catch(e) {
+    return console.log('*** ' + argv.mbtiles + ' does not exist');
+}
+
 function usage () {
     var text = [];
-    text.push('usage: node cli.js [options]');
+    text.push('usage: mbview [file] [options]');
     text.push('');
-    text.push(' --mbtiles path to mbtiles file');
-    text.push(' --port sets port to use');
+    text.push(' --mbtiles path to mbtiles file (optional)');
+    text.push(' --port sets port to use (default: 3000)');
     text.push(' --quiet or -q supress all logging except the address to visit');
     text.push(' -n don\'t automatically open the browser on start');
     text.push(' --basemap or --base or --map sets the basemap style (default: dark)');
@@ -33,7 +41,7 @@ var params = {
     sourceLayer: argv.sourceLayer || path.basename(argv.mbtiles, '.mbtiles'),
     sourceId: 'default',
     zoom: 12,
-    quiet: argv.q || argv.quiet
+    quiet: argv.q || argv.quiet,
     basemap: argv.basemap
 };