[lib] use winston for logger

- related to #3 #2 give up on making code completion work, at least
  project level module got proper hint
- enable color by default

bin/about.js

@@ -1,32 +1,23 @@
 #!/usr/bin/env node
+
 'use strict';
 const meow = require('meow');
-const chalk = require('chalk');
-const error = chalk.bold.red;
-console.log(error('Error!'));
+const configLocator = require('../lib/config/locator');
 
 const cli = meow(`
     Usage
-      $ foo <input>
+      $ about <input>
 
     Options
-      --rainbow, -r  Include a rainbow
+      --config, -c  Specify config file
 
     Examples
-      $ foo unicorns --rainbow
-      🌈 unicorns 🌈
+      $ about --config ./example/config.yaml
+      $ about -c ./example/config.yaml
 `, {
     alias: {
-        r: 'rainbow'
+        c: 'config'
     }
 });
-/*
- {
- input: ['unicorns'],
- flags: {rainbow: true},
- ...
- }
- */
-// node about.js unicorns --rainbow
-// unicorns { rainbow: true, r: true }
-console.log(cli.input[0], cli.flags);
+console.log(cli.input[0], cli.flags);
+configLocator.detectConfigFile(cli.flags);

lib/config/locator.js

@@ -0,0 +1,21 @@
+/**
+ * Created by at15 on 2016/9/6.
+ */
+const logger = require('../logger');
+const fsUtil = require('../util/fs');
+
+function detectConfigFile(flags) {
+    if (typeof flags.config === 'string') {
+        let configFile = flags.config;
+        logger.debug(`config file set as ${configFile}`);
+        // it must exist, if not we fallback to the default one and throw a warning
+        if (!fsUtil.fileExists(configFile)) {
+            logger.warn(`config file can't be found ${configFile}`);
+        }
+    }
+    logger.debug('using default config file');
+}
+
+module.exports = {
+    detectConfigFile
+};

lib/logger.js

@@ -0,0 +1,22 @@
+/**
+ * Created by at15 on 2016/9/6.
+ *
+ */
+
+const winston = require('winston');
+
+let logger = new (winston.Logger)({
+    transports: [
+        new (winston.transports.Console)({ level: 'debug', colorize: true })
+    ]
+});
+
+module.exports = {
+    // FIXME: got no type hint for the function parameters
+    // TODO: add color using chalk, don't know if winston has color by default
+    // winston is using colors instead of chalk (colors seems to have problems which are solved by chalk)
+    debug: logger.debug,
+    info: logger.info,
+    warn: logger.warn,
+    error: logger.error
+};

lib/util/fs.js

@@ -0,0 +1,18 @@
+/**
+ * Created by at15 on 2016/9/6.
+ */
+var fs = require('fs');
+
+/** @param path {string} */
+function fileExists(path) {
+    try {
+        fs.accessSync(path, fs.constants.F_OK)
+        return true;
+    } catch (e) {
+        return false;
+    }
+}
+
+module.exports = {
+    fileExists
+};

package.json

@@ -25,7 +25,9 @@
   "homepage": "https://github.com/tongquhq/about#readme",
   "dependencies": {
     "chalk": "^1.1.3",
-    "meow": "^3.7.0"
+    "js-yaml": "^3.6.1",
+    "meow": "^3.7.0",
+    "winston": "^2.2.0"
   },
   "devDependencies": {
     "chai": "3.5.0",