initial commit

.gitignore

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+### Node template
+# Logs
+logs
+*.log
+npm-debug.log*
+
+# Runtime data
+pids
+*.pid
+*.seed
+
+# Directory for instrumented libs generated by jscoverage/JSCover
+lib-cov
+
+# Coverage directory used by tools like istanbul
+coverage
+
+# Grunt intermediate storage (http://gruntjs.com/creating-plugins#storing-task-files)
+.grunt
+
+# node-waf configuration
+.lock-wscript
+
+# Compiled binary addons (http://nodejs.org/api/addons.html)
+build/Release
+
+# Dependency directories
+node_modules
+jspm_packages
+
+# Optional npm cache directory
+.npm
+
+# Optional REPL history
+.node_repl_history
+### JetBrains template
+# Covers JetBrains IDEs: IntelliJ, RubyMine, PhpStorm, AppCode, PyCharm, CLion, Android Studio and Webstorm
+# Reference: https://intellij-support.jetbrains.com/hc/en-us/articles/206544839
+
+# User-specific stuff:
+.idea**
+
+# Sensitive or high-churn files:
+.idea/dataSources.ids
+.idea/dataSources.xml
+.idea/dataSources.local.xml
+.idea/sqlDataSources.xml
+.idea/dynamic.xml
+.idea/uiDesigner.xml
+
+# Gradle:
+.idea/gradle.xml
+.idea/libraries
+
+# Mongo Explorer plugin:
+.idea/mongoSettings.xml
+
+## File-based project format:
+*.iws
+
+## Plugin-specific files:
+
+# IntelliJ
+/out/
+
+# mpeltonen/sbt-idea plugin
+.idea_modules/
+
+# JIRA plugin
+atlassian-ide-plugin.xml
+
+# Crashlytics plugin (for Android Studio and IntelliJ)
+com_crashlytics_export_strings.xml
+crashlytics.properties
+crashlytics-build.properties
+fabric.properties
+
+# Created by .ignore support plugin (hsz.mobi)

README.MD

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+traverse directory examples
+=================
+
+
+
+### [example 01](example_01/traverser.js)
+
+the most simple one, with callback hell (anonymous function), and use recursive.
+
+
+
+### [example 02](example_01/traverser.js)
+
+Eliminate recursive and callback hell. use named function instead of anonymous function. 

example_01/traverser.js

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+#!/usr/bin/env node
+'use strict';
+
+var fs = require('fs');
+var path = require('path');
+
+/**
+ * @param filePath the start path of traverse
+ * @param callback (err, res). res is the absolute path of file.
+ */
+function traverse(filePath, callback) {
+
+    filePath = path.resolve(filePath);
+    // get file stats
+    fs.lstat(filePath, function(err, stats) {
+        if (err) {
+            callback(err);
+        } else {
+            // check whether a file or dir
+            if (stats.isDirectory()) {
+                // get all files and dirs in directory
+                fs.readdir(filePath, function (err, files) {
+                    if (err) {
+                        callback(err);
+                    } else {
+                        files.forEach(function(item) {
+                            // call traverse recursively
+                            traverse(path.resolve(filePath, item), callback);
+                        });
+                    }
+                });
+            } else {
+                // return the file path.
+                callback(null, filePath);
+            }
+        }
+    });
+}
+
+/*  call traverse */
+traverse(process.argv[2], function(err, res) {
+    if (err) {
+        console.error(err);
+    } else {
+        console.log(res);
+    }
+});

example_02/traverser.js

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+#!/usr/bin/env node
+'use strict';
+
+var fs = require('fs');
+var path = require('path');
+
+/**
+ * @param filePath the start path of traverse
+ * @param callback (err, res). res is the absolute path of file.
+ */
+function traverse(filePath, callback) {
+    // initial state
+    var list = [ path.resolve(filePath) ];
+    // start traverse
+    next();
+
+    function next() {
+        var current = list.shift();
+        if (current) {
+            // get file state info
+            fs.lstat(current, check.bind(null, current));
+        }
+    }
+
+    function check(current, err, stats) {
+        if (err) {
+            callback(err);
+        } else {
+            // check whether a file or dir
+            if (stats.isDirectory()) {
+                // get all files and dirs in directory
+                fs.readdir(current, add_subdir.bind(null, current))
+            } else {
+                // return filePath
+                callback(null, current);
+                next();
+            }
+        }
+    }
+
+    function add_subdir(current, err, files) {
+        if (err) {
+            callback(err);
+        } else {
+            // list and resolve all file in sub dir.
+            var paths = files.map(function (item) {
+                return path.resolve(current, item);
+            });
+            // add to list
+            list = list.concat(paths);
+            next();
+        }
+    }
+}
+
+
+
+
+
+/*  call traverse */
+traverse(process.argv[2], function(err, res) {
+    if (err) {
+        console.error(err);
+    } else {
+        console.log(res);
+    }
+});