use arrow functions

README.md

@@ -72,7 +72,7 @@ const Gpio = require('onoff').Gpio;
 const led = new Gpio(17, 'out');
 const button = new Gpio(4, 'in', 'both');
 
-button.watch(function (err, value) {
+button.watch((err, value) => {
   led.writeSync(value);
 });
 ```
@@ -101,15 +101,15 @@ const Gpio = require('onoff').Gpio;
 const led = new Gpio(17, 'out');
 const button = new Gpio(4, 'in', 'both');
 
-button.watch(function (err, value) {
+button.watch((err, value) => {
   if (err) {
     throw err;
   }
 
   led.writeSync(value);
 });
 
-process.on('SIGINT', function () {
+process.on('SIGINT', () => {
   led.unexport();
   button.unexport();
 });
@@ -137,15 +137,15 @@ const Gpio = require('onoff').Gpio;
 const led = new Gpio(17, 'out');
 const button = new Gpio(4, 'in', 'rising', {debounceTimeout: 10});
 
-button.watch(function (err, value) {
+button.watch((err, value) => {
   if (err) {
     throw err;
   }
 
   led.writeSync(led.readSync() ^ 1);
 });
 
-process.on('SIGINT', function () {
+process.on('SIGINT', () => {
   led.unexport();
   button.unexport();
 });
@@ -160,7 +160,7 @@ can be used to achieve this.
 ```js
 const Gpio = require('onoff').Gpio;
 
-const useLed = function (led, value) {
+const useLed = (led, value) => {
   led.writeSync(value);
 }
 
@@ -171,7 +171,7 @@ if (Gpio.accessible) {
   // more real code here
 } else {
   led = { 
-    writeSync: function (value) {
+    writeSync: (value) => {
       console.log('virtual led now uses value: ' + value);
     }
   };
@@ -373,12 +373,12 @@ const led = new Gpio(17, 'out');    // Export GPIO17 as an output
 
 // Toggle the state of the LED connected to GPIO17 every 200ms.
 // Here synchronous methods are used. Asynchronous methods are also available.
-const iv = setInterval(function () {
+const iv = setInterval(() => {
   led.writeSync(led.readSync() ^ 1); // 1 = on, 0 = off :)
 }, 200);
 
 // Stop blinking the LED and turn it off after 5 seconds
-setTimeout(function () {
+setTimeout(() => {
   clearInterval(iv); // Stop blinking
   led.writeSync(0);  // Turn LED off
   led.unexport();    // Unexport GPIO and free resources
@@ -395,27 +395,29 @@ const led = new Gpio(17, 'out');    // Export GPIO17 as an output
 
 // Toggle the state of the LED connected to GPIO17 every 200ms 'count' times.
 // Here asynchronous methods are used. Synchronous methods are also available.
-(function blink(count) {
+const blinkLed = (count) => {
   if (count <= 0) {
     return led.unexport();
   }
 
-  led.read(function (err, value) { // Asynchronous read
+  led.read((err, value) => { // Asynchronous read
     if (err) {
       throw err;
     }
 
-    led.write(value ^ 1, function (err) { // Asynchronous write
+    led.write(value ^ 1, (err) => { // Asynchronous write
       if (err) {
         throw err;
       }
     });
   });
 
-  setTimeout(function () {
-    blink(count - 1);
+  setTimeout(() => {
+    blinkLed(count - 1);
   }, 200);
-}(25));
+};
+
+blinkLed(25);
 ```
 
 ## How Does onoff Work?

examples/blink-led-async.js

@@ -5,25 +5,27 @@ const led = new Gpio(17, 'out');       // Export GPIO17 as an output
 
 // Toggle the state of the LED connected to GPIO17 every 200ms 'count' times.
 // Here asynchronous methods are used. Synchronous methods are also available.
-(function blink(count) {
+const blinkLed = (count) => {
   if (count <= 0) {
     return led.unexport();
   }
 
-  led.read(function (err, value) { // Asynchronous read
+  led.read((err, value) => { // Asynchronous read
     if (err) {
       throw err;
     }
 
-    led.write(value ^ 1, function (err) { // Asynchronous write
+    led.write(value ^ 1, (err) => { // Asynchronous write
       if (err) {
         throw err;
       }
     });
   });
 
-  setTimeout(function () {
-    blink(count - 1);
+  setTimeout(() => {
+    blinkLed(count - 1);
   }, 200);
-}(25));
+};
+
+blinkLed(25);
 

examples/blink-led.js

@@ -5,12 +5,12 @@ const led = new Gpio(17, 'out');       // Export GPIO17 as an output
 
 // Toggle the state of the LED connected to GPIO17 every 200ms.
 // Here synchronous methods are used. Asynchronous methods are also available.
-const iv = setInterval(function () {
+const iv = setInterval(() => {
   led.writeSync(led.readSync() ^ 1); // 1 = on, 0 = off :)
 }, 200);
 
 // Stop blinking the LED and turn it off after 5 seconds
-setTimeout(function () {
+setTimeout(() => {
   clearInterval(iv); // Stop blinking
   led.writeSync(0);  // Turn LED off
   led.unexport();    // Unexport GPIO and free resources

examples/debounce-button.js

@@ -4,15 +4,15 @@ const Gpio = require('../onoff').Gpio;
 const led = new Gpio(17, 'out');
 const button = new Gpio(4, 'in', 'rising', {debounceTimeout: 10});
 
-button.watch(function (err, value) {
+button.watch((err, value) => {
   if (err) {
     throw err;
   }
 
   led.writeSync(led.readSync() ^ 1);
 });
 
-process.on('SIGINT', function () {
+process.on('SIGINT', () => {
   led.unexport();
   button.unexport();
 });

examples/light-switch.js

@@ -4,15 +4,15 @@ const Gpio = require('../onoff').Gpio;
 const led = new Gpio(17, 'out');
 const button = new Gpio(4, 'in', 'both');
 
-button.watch(function (err, value) {
+button.watch((err, value) => {
   if (err) {
     throw err;
   }
 
   led.writeSync(value);
 });
 
-process.on('SIGINT', function () {
+process.on('SIGINT', () => {
   led.unexport();
   button.unexport();
 });

examples/wait-for-interrupt.js

@@ -10,7 +10,7 @@ console.log('Please press the button on GPIO4...');
 
 // The callback passed to watch will be invoked when the button connected to
 // GPIO4 is pressed
-button.watch(function (err, value) {
+button.watch((err, value) => {
   if (err) {
     throw err;
   }

onoff.js

@@ -14,7 +14,7 @@ const LOW_BUF = Buffer.from('0');
 const HIGH = 1;
 const LOW = 0;
 
-const waitForAccessPermission = function (paths) {
+const waitForAccessPermission = (paths) => {
   paths.forEach((path) => {
     let tries = 0;
 

test/change-configuration.js

@@ -6,7 +6,7 @@ const Gpio = require('../onoff').Gpio;
 let output = new Gpio(8, 'out');
 let input = new Gpio(7, 'in', 'both');
 
-function watchWithSecondConfiguration() {
+const watchWithSecondConfiguration = () => {
   input.watch((err, value) => {
     assert(!err, 'error during interrupt detection');
     assert(value === 1, 'expected interrupt on rising edge');
@@ -22,7 +22,7 @@ function watchWithSecondConfiguration() {
   output.writeSync(1);
 }
 
-function changeConfiguration() {
+const changeConfiguration = () => {
   input.unwatchAll();
 
   let temp = output;
@@ -45,7 +45,7 @@ function changeConfiguration() {
   watchWithSecondConfiguration();
 }
 
-function watchWithFirstConfiguration() {
+const watchWithFirstConfiguration = () => {
   input.watch((err, value) => {
     assert(!err, 'error during interrupt detection');
     assert(value === 1, 'expected interrupt on rising edge');

test/debounce.js

@@ -8,7 +8,7 @@ const button = new Gpio(7, 'in', 'both', {debounceTimeout: 10});
 let buttonPressedCount = 0;
 let buttonReleasedCount = 0;
 
-function simulateToggleButtonStateWithBounce(cb) {
+const simulateToggleButtonStateWithBounce = (cb) => {
   let toggleCount = 0;
 
   const iv = setInterval(() => {
@@ -22,7 +22,7 @@ function simulateToggleButtonStateWithBounce(cb) {
   }, 2);
 }
 
-function simulatePressAndReleaseButtonWithBounce() {
+const simulatePressAndReleaseButtonWithBounce = () => {
   simulateToggleButtonStateWithBounce(() => {
     setTimeout(() => {
       simulateToggleButtonStateWithBounce(() => {

test/many-interrupts.js

@@ -9,12 +9,12 @@ let toggleCount = 0;
 let falling = 0;
 let rising = 0;
 
-function toggleOutput() {
+const toggleOutput = () => {
   output.writeSync(output.readSync() ^ 1);
   toggleCount += 1;
 }
 
-function interrupt(err, value) {
+const interrupt = (err, value) => {
   if (err) {
     throw err;
   }

test/output-with-edge-bug.js

@@ -10,7 +10,7 @@
 const Gpio = require('../onoff').Gpio;
 const assert = require('assert');
 
-function ensureGpio17Unexported(cb) {
+const ensureGpio17Unexported = (cb) => {
   let led = new Gpio(17, 'out');
 
   led.unexport();

test/performance-interrupt.js

@@ -15,7 +15,7 @@ let irqCount = 0;
 let iv;
 
 // Exit handler
-function exit() {
+const exit = () => {
   input.unexport();
   output.unexport();
 

unittest/mocks/epoll.js

@@ -1,3 +1,4 @@
+'use strict';
 
 class Epoll {
 

unittest/watching.js

@@ -1,4 +1,4 @@
-"use strict";
+'use strict';
 
 const assert = require('assert');
 const mockFs = require('mock-fs');
@@ -12,6 +12,20 @@ const Gpio = require('../onoff').Gpio;
 describe('watching', () => {
   let pin;
 
+  const listener1 = (err, value) => {
+    if (err) {
+      throw err;
+    }
+    console.log(`listener1: value is ${value}`);
+  }
+
+  const listener2 = (err, value) => {
+    if (err) {
+      throw err;
+    }
+    console.log(`listener2: value is ${value}`);
+  }
+
   beforeEach(() => {
     mockFs({
       '/sys/class/gpio': {
@@ -106,19 +120,4 @@ describe('watching', () => {
     pin.unexport();
     mockFs.restore();
   });
-
-  function listener1(err, value) {
-    if (err) {
-      throw err;
-    }
-    console.log(`listener1: value is ${value}`);
-  }
-
-  function listener2(err, value) {
-    if (err) {
-      throw err;
-    }
-    console.log(`listener2: value is ${value}`);
-  }
-
-});
+});