Implement 'list <keyword>'

* fixes invalid usage of yargs command.

Signed-off-by: Eric Wang <skygragon@gmail.com>

Author: skygragon

README.md

@@ -55,6 +55,9 @@ Navigate all the problems. The heading `✔` means you have AC-ed the problem.
     ✔ [  1] Two Sum                                                      Easy   (25.6%)
 
 * `-D` to only show undone problems.
+* `-l` to filter by level.
+* `-s` to show statistic counters.
+* `lc list <keyword>` to search by keyword.
 
 ### 3. Prepare
 

lib/commands/list.js

@@ -5,20 +5,26 @@ var core = require('../core');
 var h = require('../helper');
 
 var cmd = {
-  command: 'list [--level|-l] [--stat|-s] [--undone|-D]',
+  command: 'list [keyword]',
   desc:    'List all problems.',
   builder: {
+    keyword: {
+      type:     'string',
+      describe: 'keyword used to search problems.'
+    },
     level: {
       alias:    'l',
       choices:  ['easy', 'medium', 'hard', 'e', 'm', 'h'],
       describe: 'Filter problems by level.'
     },
     stat: {
       alias:    's',
+      type:     'boolean',
       describe: 'Show stats of the problems.'
     },
     undone: {
       alias:    'D',
+      type:     'boolean',
       describe: 'List undone problems.'
     }
   }
@@ -42,6 +48,12 @@ cmd.handler = function(argv) {
       });
     }
 
+    if (argv.keyword) {
+      problems = _.filter(problems, function(x) {
+        return x.name.toLowerCase().indexOf(argv.keyword) !== -1;
+      });
+    }
+
     var stat = {};
     problems.forEach(function(problem) {
       stat[problem.level] = (stat[problem.level] || 0) + 1;

lib/commands/show.js

@@ -8,7 +8,7 @@ var core = require('../core');
 var h = require('../helper');
 
 var cmd = {
-  command: 'show <keyword> [--gen|-g] [--lang|-l]',
+  command: 'show <keyword>',
   desc:    'Show problem details.',
   builder: {
     keyword: {

lib/commands/test.js

@@ -5,7 +5,7 @@ var core = require('../core');
 var h = require('../helper');
 
 var cmd = {
-  command: 'test <filename> [--testcase|-t] [-i]',
+  command: 'test <filename>',
   desc:    'Run test case to leetcode.',
   builder: {
     filename: {

lib/commands/update.js

@@ -1,5 +1,5 @@
 var cmd = {
-  command: 'update [--cached|-c] [--all|-a]',
+  command: 'update',
   desc:    'Update problems list from leetcode.',
   builder: {
     all: {

lib/commands/user.js

@@ -3,7 +3,7 @@ var prompt = require('prompt');
 var core = require('../core');
 
 var cmd = {
-  command: 'user [--login|-l] [--logout|-L]',
+  command: 'user',
   desc:    'Login/logout with leetcode account.',
   builder: {
     login: {