enhance: Return a promise if not provide callback

README.md

@@ -14,15 +14,20 @@ $ npm install node-df
 
 ### Basic
 
+It will return a promise if the callback isn't passed.
+
 ```javascript
 var
     df = require('node-df');
-
+// with callback
 df(function (error, response) {
     if (error) { throw error; }
 
     console.log(JSON.stringify(response, null, 2));
 });
+// with promises:
+df()
+    .then((response) => console.log(JSON.stringify(response, null, 2)));
 ```
 
 Output from `df` looks like this:

lib/index.js

@@ -1,41 +1,53 @@
 var exec = require('child_process').exec
-var parse = require('./parse')
+var utils = require('./utils')
+var parsePosix = require('./parse-posix')
+var parseWin = require('./parse-win')
+var path = require('path')
 
 module.exports = function df(aOptions, aCallback) {
     var options
     var callback
 
-    if (typeof aOptions === 'function') {
+    if (!aCallback && !aOptions) { // df()
+        callback = utils.createPromiseCallback()
         options = {}
+    } else if (!aCallback && typeof aOptions === 'function') { // df(cb)
         callback = aOptions
-    } else {
+        options = {}
+    } else if (!aCallback && typeof aOptions !== 'function') {// cb(options)
+        callback = utils.createPromiseCallback()
         options = aOptions
+    } else {// df(options, cb)
         callback = aCallback
+        options = aOptions
     }
 
-    // TODO: this should throw an error because invoking df without a callback function is pointless.
-    // It's a breaking change to be made after releasing 0.1.4
-    if (typeof callback !== 'function') {
-        callback = function() {}
-    }
-
-    // TODO: this should invoke callback with an error
-    // It's a breaking change to be made after releasing 0.1.4
-    if (typeof options !== 'object') {
-        options = {}
-    }
-
-    // TODO: snould validate options and merge with defaults
+    // TODO: should validate options and merge with defaults
     // It's a breaking change to be made after releasing 0.1.4
 
     // TODO: should throw if prefixMultiplier is not a string
     // It should invoke callback with `err` but it's a breaking change
 
     // TODO: should fail if unit is not a string
-
-    var command = 'df -kP'
-    if (options.file) {
-        command += ' ' + options.file
+    var command = null;
+    var isWin = process.platform === 'win32'
+    var file = options.file
+    if (isWin) {
+        var disk = null
+        command = 'wmic LOGICALDISK '
+        if (file) {
+            file = path.win32.normalize(file)
+            disk = path.parse(file).root.slice(0, -1)
+            command += disk
+        } else {
+            command += ' where "DRIVETYPE=3 or DRIVETYPE=4"'
+        }
+        command += ' get name, filesystem, size, freespace'
+    } else {
+        var command = 'df -kP'
+        if (file) {
+            command += ' ' + file
+        }
     }
 
     exec(command, function(err, stdout, stderr) {
@@ -49,7 +61,12 @@ module.exports = function df(aOptions, aCallback) {
             return
         }
 
-        var entries = parse(stdout, options)
+        var entries = null;
+        if (isWin) {
+            entries = parseWin(stdout, options)
+        } else {
+            entries = parsePosix(stdout, options)
+        }
 
         callback(null, entries)
     })

lib/parse-win.js

@@ -0,0 +1,50 @@
+var format = require('./format')
+var calcMultiplier = require('./calcMultiplier')
+
+module.exports = function (stdout, options) {
+    // TODO: this should be removed because it never happens.
+    // Nonetheless, I want to consider it a breaking changed that's to be made after releasing 0.1.4
+    if (!stdout) {
+        return void 0
+    }
+
+    // TODO: `options.prefixMultiplier` should become `options.unit`
+    // I should deprecate the use of `options.prefixMultiplier` in 0.1.4
+    var multiplier = calcMultiplier(options.prefixMultiplier)
+    var precision = options.precision
+    // TODO: `options.isDisplayPrefixMultiplier` should become `options.showUnit`
+    // I should deprecate the use of options.isDisplayPrefixMultiplier in 0.1.4
+    var unit = options.isDisplayPrefixMultiplier ? options.prefixMultiplier : null
+
+    return stdout
+        .trim()
+        .split(/\r\r\n/) // split into rows
+        .slice(1) // strip column headers away
+        .map(function (row) {
+            var columns = row
+                .trim()
+                // one or more whitespaces followed by one or more digits
+                // must be interpreted as column delimiter
+                .replace(/\s+(\d+)/g, '\t$1')
+                // one or more whitespaces followed by a letter
+                // must be interpreted as column delimiter
+                .replace(/\s+([a-zA-Z])/g, '\t$1')
+                // comma followed by one or more whitespaces must be
+                // interpreted as the last column delimiter
+                .replace(/(\:)\s+/g, '$1\t')
+                // split into columns
+                .split(/\t/)
+            var size = parseInt(columns[3], 10)
+            var free = parseInt(columns[1], 10)
+            var used = size - free
+            var capacity = 1 - free / size
+            return {
+                filesystem: columns[0],
+                size: format(size, multiplier, precision, unit),
+                used: format(used, multiplier, precision, unit),
+                available: format(free, multiplier, precision, unit),
+                capacity: precision ? capacity.toFixed(precision) : capacity,
+                mount: columns[2],
+            }
+        })
+}

lib/utils.js

@@ -0,0 +1,16 @@
+'use strict';
+// From loopback
+// https://github.com/strongloop/loopback/blob/77a35231dc0e8a480feb5b8e9e48429ab5bdd037/lib/utils.js#L16
+exports.createPromiseCallback = function createPromiseCallback() {
+    var cb = null;
+    var promise = new Promise(function(resolve, reject) {
+        cb = function(err, data) {
+            if (err) {
+                return reject(err);
+            }
+            return resolve(data);
+        };
+    });
+    cb.promise = promise;
+    return cb;
+};

package.json

@@ -1,13 +1,13 @@
 {
-    "name": "node-df",
-    "version": "0.1.4",
+    "name": "node-df-win-posix",
+    "version": "0.3.0",
     "description":
         "A cross-platform Node.js wrapper around the standard Unix computer program, df.",
     "main": "lib/index.js",
     "scripts": {
         "precommit": "lint-staged",
         "test:coverage": "npm test -- --coverage",
-        "test": "jest"
+        "test": "jest --env=node"
     },
     "author": "Adriano Di Giovanni <[email protected]> (http://adrianodigiovanni.com/)",
     "license": "MIT",
@@ -31,15 +31,15 @@
     },
     "repository": {
         "type": "git",
-        "url": "https://github.com/adriano-di-giovanni/node-df.git"
+        "url": "https://github.com/dreamdevil00/node-df.git"
     },
     "keywords": ["node", "df", "disk", "free", "diskfree"],
     "bugs": {
-        "url": "https://github.com/adriano-di-giovanni/node-df/issues"
+        "url": "https://github.com/dreamdevil00/node-df/issues"
     },
     "lint-staged": {
         "*.js": ["eslint --fix", "git add"],
         "*.json": ["prettier --write", "git add"]
     },
-    "homepage": "https://github.com/adriano-di-giovanni/node-df"
+    "homepage": "https://github.com/dreamdevil00/node-df.git"
 }