refactor two-column table layout so that we can use it for examples and usage

Author: bcoe

index.js

@@ -75,7 +75,7 @@ function Argv (processArgs, cwd) {
 
     var examples = [];
     self.example = function (cmd, description) {
-        examples.push([cmd, description]);
+        examples.push([cmd, description || '']);
         return self;
     };
     self.getExamples = function() {

lib/usage.js

@@ -86,19 +86,16 @@ function Usage (yargs) {
                 example[0] = example[0].replace(/\$0/g, yargs.$0);
             });
 
-            var commandlen = longest(examples.map(function (a) {
-                return a[0];
-            }));
-
-            var exampleLines = examples.map(function(example) {
-                var command = example[0];
-                var description = example[1];
-                command += Array(commandlen + 5 - command.length).join(' ');
-                return '  ' + command + description;
+            var examplesTable = {};
+            examples.forEach(function(example) {
+                examplesTable[example[0]] = {
+                    desc: example[1],
+                    extra: ''
+                };
             });
 
-            exampleLines.push('');
-            help = exampleLines.concat(help);
+            help = formatTable(examplesTable, 5).concat(help);
+            help.push('');
             help.unshift('Examples:');
         }
 
@@ -114,6 +111,7 @@ function Usage (yargs) {
                 return -1 == (options.alias[alias] || []).indexOf(key);
             });
         });
+
         var switches = keys.reduce(function (acc, key) {
             acc[key] = [ key ].concat(options.alias[key] || [])
                 .map(function (sw) {
@@ -124,44 +122,17 @@ function Usage (yargs) {
             return acc;
         }, {});
 
-        var switchlen = longest(Object.keys(switches).map(function (s) {
-            return switches[s] || '';
-        }));
-
-        var desclen = longest(Object.keys(descriptions).map(function (d) {
-            return descriptions[d] || '';
-        }));
-
+        var switchTable = {};
         keys.forEach(function (key) {
             var kswitch = switches[key];
             var desc = descriptions[key] || '';
-
-            if (wrap) {
-                desc = wordwrap(switchlen + 4, wrap)(desc)
-                    .slice(switchlen + 4)
-                ;
-            }
-
-            var spadding = new Array(
-                Math.max(switchlen - kswitch.length + 3, 0)
-            ).join(' ');
-
-            var dpadding = new Array(
-                Math.max(desclen - desc.length + 1, 0)
-            ).join(' ');
-
             var type = null;
 
             if (options.boolean[key]) type = '[boolean]';
             if (options.count[key]) type = '[count]';
             if (options.string[key]) type = '[string]';
             if (options.normalize[key]) type = '[string]';
 
-            if (!wrap && dpadding.length > 0) {
-                desc += dpadding;
-            }
-
-            var prelude = '  ' + kswitch + spadding;
             var extra = [
                 type,
                 demanded[key]
@@ -174,6 +145,59 @@ function Usage (yargs) {
                     : null
             ].filter(Boolean).join('  ');
 
+            switchTable[kswitch] = {
+              desc: desc,
+              extra: extra
+            };
+        });
+        help.push.apply(help, formatTable(switchTable, 3));
+
+        if (keys.length) help.push('');
+        return help.join('\n');
+    };
+
+    self.showHelp = function (level) {
+        level = level || 'error';
+        console[level](self.help());
+    }
+
+    // word-wrapped two-column layout used by
+    // examples and options.
+    function formatTable (table, padding) {
+        var output = [];
+
+        // determine lengths of left column, and
+        // description column.
+        var llen = longest(Object.keys(table));
+
+        var desclen = longest(Object.keys(table).map(function (k) {
+            return table[k].desc;
+        }));
+
+        Object.keys(table).forEach(function(left) {
+            var desc = table[left].desc,
+              extra = table[left].extra;
+
+            if (wrap) {
+                desc = wordwrap(llen + padding + 1, wrap)(desc)
+                    .slice(llen + padding + 1)
+                ;
+            }
+
+            var lpadding = new Array(
+                Math.max(llen - left.length + padding, 0)
+            ).join(' ');
+
+            var dpadding = new Array(
+                Math.max(desclen - desc.length + 1, 0)
+            ).join(' ');
+
+            if (!wrap && dpadding.length > 0) {
+                desc += dpadding;
+            }
+
+            var prelude = '  ' + left + lpadding;
+
             var body = [ desc, extra ].filter(Boolean).join('  ');
 
             if (wrap) {
@@ -182,7 +206,7 @@ function Usage (yargs) {
                     + (dlines.length === 1 ? prelude.length : 0)
 
                 if (extra.length > wrap) {
-                    body = desc + '\n' + wordwrap(switchlen + 4, wrap)(extra)
+                    body = desc + '\n' + wordwrap(llen + 4, wrap)(extra)
                 } else {
                     body = desc + (dlen + extra.length > wrap - 2
                         ? '\n'
@@ -194,18 +218,13 @@ function Usage (yargs) {
                 }
             }
 
-            help.push(prelude + body);
+            output.push(prelude + body);
         });
 
-        if (keys.length) help.push('');
-        return help.join('\n');
-    };
-
-    self.showHelp = function (level) {
-        level = level || 'error';
-        console[level](self.help());
+        return output;
     }
 
+    // find longest string in array of strings.
     function longest (xs) {
         return Math.max.apply(
             null,

test/usage.js

@@ -551,7 +551,7 @@ describe('usage tests', function () {
         r.should.have.property('exit').and.be.ok;
         r.errors.join('\n').split(/\n+/).should.deep.equal([
             'Examples:',
-            '  ./usage something         description',
+            '  ./usage something         description      ',
             '  ./usage something else    other description',
             'Options:',
             '  -y  [required]',