Add byteLength method and hasState property

.eslintignore

@@ -0,0 +1,16 @@
+# Node.js stuff
+node_modules
+package-lock.json
+
+# Editors
+*~
+*sublime-*
+/.idea
+
+# Development environment
+/coverage
+/benchmarks/node_envs
+/generation/source-data
+
+# Temporarily excluded
+/generation/research

.eslintrc.yml

@@ -0,0 +1,29 @@
+env:
+    commonjs: true
+    es6: true
+    node: true
+    mocha: true
+extends: "eslint:recommended"
+parserOptions:
+    ecmaVersion: 6
+plugins:
+    - es
+rules:
+    strict: "error"
+    no-console: "error"
+    no-template-curly-in-string: "error"
+    consistent-return: "error"
+    eqeqeq: ["error", "smart"]
+    no-throw-literal: "error"
+    no-eval: "error"
+    no-implied-eval: "error"
+    # no-use-before-define: "error"  # TODO
+    # no-var: "error"  # TODO
+    block-scoped-var: "error"
+    prefer-const: "error"
+    yoda: ["error", "never", { "exceptRange": true }]
+
+    # 'es' pluin rules. See https://mysticatea.github.io/eslint-plugin-es/rules/
+    # Disallow the ones that are not supported by Node 4.5
+    es/no-destructuring: "error"
+    es/no-default-parameters: "error"

.github/dependabot.yml

@@ -3,9 +3,9 @@
 
 version: 2
 updates:
-  - package-ecosystem: "npm"
-    directory: "/"
-    schedule:
-      interval: "daily"
-    allow:
-      - dependency-type: production
+    - package-ecosystem: "npm"
+      directory: "/"
+      schedule:
+          interval: "daily"
+      allow:
+          - dependency-type: production

.lintstagedrc.js

@@ -0,0 +1,10 @@
+const { CLIEngine } = require("eslint");
+const cli = new CLIEngine({});
+
+// This hack is recommended by lint-staged authors:
+// https://github.com/okonet/lint-staged#how-can-i-ignore-files-from-eslintignore-
+module.exports = {
+    "*.js": (files) =>
+        "eslint --max-warnings=0 " + files.filter((file) => !cli.isPathIgnored(file)).join(" "),
+    "*.{js,json,yml,md,ts}": "prettier --write",
+};

.prettierignore

@@ -0,0 +1,21 @@
+# Node.js stuff
+node_modules
+package-lock.json
+
+# Editors
+*~
+*sublime-*
+/.idea
+
+# Development environment
+/coverage
+/benchmarks/node_envs
+/generation/source-data
+
+# Generated data
+/encodings/tables
+/encodings/sbcs-data-generated.js
+Changelog.md
+
+# Temporarily excluded
+/generation/research

.prettierrc.yml

@@ -0,0 +1,3 @@
+tabWidth: 4
+useTabs: false
+printWidth: 100

.travis.yml

@@ -1,19 +1,31 @@
 language: node_js
 node_js:
-  - "0.10"
-  - "0.11"
-  - "0.12"
-  - "iojs"
-  - "4"
-  - "6"
-  - "8"
-  - "10"
-  - "12"
-  - "node"
+    - "4.5.0" # Oldest supported version
+    - "5.10.0" # Oldest supported version from version 5.x
+    - "4"
+    - "6"
+    - "8"
+    - "10"
+    - "12"
+    - "node"
+
+# Only install test-related modules on older Node versions
+install: npm run-script test-install
 
 jobs:
-  include:
-    - name: webpack
-      node_js: "12"
-      install: cd test/webpack; npm install
-      script: npm test
+    include:
+        - name: webpack
+          node_js: "12"
+          install: cd test/webpack; npm install
+          script: npm test
+
+        - name: node-web-backend
+          node_js: "12"
+          script: npm run-script test-node-web
+
+        - name: linters
+          node_js: "12"
+          install: npm install
+          script:
+              - eslint --max-warnings 0 .
+              - prettier --check .

README.md

@@ -1,14 +1,14 @@
 ## iconv-lite: Pure JS character encoding conversion
 
- * No need for native code compilation. Quick to install, works on Windows and in sandboxed environments like [Cloud9](http://c9.io).
- * Used in popular projects like [Express.js (body_parser)](https://github.com/expressjs/body-parser), 
-   [Grunt](http://gruntjs.com/), [Nodemailer](http://www.nodemailer.com/), [Yeoman](http://yeoman.io/) and others.
- * Faster than [node-iconv](https://github.com/bnoordhuis/node-iconv) (see below for performance comparison).
- * Intuitive encode/decode API, including Streaming support.
- * In-browser usage via [browserify](https://github.com/substack/node-browserify) or [webpack](https://webpack.js.org/) (~180kb gzip compressed with Buffer shim included).
- * Typescript [type definition file](https://github.com/ashtuchkin/iconv-lite/blob/master/lib/index.d.ts) included.
- * React Native is supported (need to install `stream` module to enable Streaming API).
- * License: MIT.
+-   No need for native code compilation. Quick to install, works on Windows and in sandboxed environments like [Cloud9](http://c9.io).
+-   Used in popular projects like [Express.js (body_parser)](https://github.com/expressjs/body-parser),
+    [Grunt](http://gruntjs.com/), [Nodemailer](http://www.nodemailer.com/), [Yeoman](http://yeoman.io/) and others.
+-   Faster than [node-iconv](https://github.com/bnoordhuis/node-iconv) (see below for performance comparison).
+-   Intuitive encode/decode API, including Streaming support.
+-   In-browser usage via [browserify](https://github.com/substack/node-browserify) or [webpack](https://webpack.js.org/) (~180kb gzip compressed with Buffer shim included).
+-   Typescript [type definition file](https://github.com/ashtuchkin/iconv-lite/blob/master/lib/index.d.ts) included.
+-   React Native is supported (need to install `stream` module to enable Streaming API).
+-   License: MIT.
 
 [![NPM Stats](https://nodei.co/npm/iconv-lite.png)](https://npmjs.org/package/iconv-lite/)  
 [![Build Status](https://travis-ci.org/ashtuchkin/iconv-lite.svg?branch=master)](https://travis-ci.org/ashtuchkin/iconv-lite)
@@ -17,67 +17,92 @@
 [![npm bundle size](https://img.shields.io/bundlephobia/min/iconv-lite.svg)](https://npmjs.org/package/iconv-lite/)
 
 ## Usage
+
 ### Basic API
+
 ```javascript
-var iconv = require('iconv-lite');
+var iconv = require("iconv-lite");
 
 // Convert from an encoded buffer to a js string.
-str = iconv.decode(Buffer.from([0x68, 0x65, 0x6c, 0x6c, 0x6f]), 'win1251');
+str = iconv.decode(Buffer.from([0x68, 0x65, 0x6c, 0x6c, 0x6f]), "win1251");
 
 // Convert from a js string to an encoded buffer.
-buf = iconv.encode("Sample input string", 'win1251');
+buf = iconv.encode("Sample input string", "win1251");
 
 // Check if encoding is supported
-iconv.encodingExists("us-ascii")
+iconv.encodingExists("us-ascii");
+
+// Calculate the actual length in bytes.
+len = iconv.byteLength("Hello, world! 😀", "utf16be");
+
+// Get a decoder and decode two different buffers into a single string, the decoder keeps state between buffers
+var utf8Decoder = iconv.getDecoder("utf8");
+var bytes1 = Buffer.from([0x20, 0x23, 0xe2]); // space, # and part of ☣
+var bytes2 = Buffer.from([0x98, 0xa3]); // the rest of ☣
+var str = utf8Decoder.write(bytes1);
+// You can check if the decoder has state currently
+var hasState = utf8Decoder.hasState; // true;
+str += utf8Decoder.write(bytes2);
+var hasState = utf8Decoder.hasState; // false;
+
+// The same for encoder, you rarely need to care about the encoder's state, except for some special encoders and surrogate pair
+var utf8Encoder = iconv.getEncoder("utf8");
+var bytes = utf8Encoder.write("Hi \uD83D");
+var hasState = utf8Encoder.hasState; // true
+bytes = bytes.concat([utf8Encoder.write("\uDE00")]);
+hasState = utf8Encoder.hasState; // false
+
+// Use the "end" method to get the remaining data in encoder/decoder's state and clear the state
+var bytes = encoder.end();
+var str = decoder.end();
 ```
 
 ### Streaming API
-```javascript
 
+```javascript
 // Decode stream (from binary data stream to js strings)
-http.createServer(function(req, res) {
-    var converterStream = iconv.decodeStream('win1251');
+http.createServer(function (req, res) {
+    var converterStream = iconv.decodeStream("win1251");
     req.pipe(converterStream);
 
-    converterStream.on('data', function(str) {
+    converterStream.on("data", function (str) {
         console.log(str); // Do something with decoded strings, chunk-by-chunk.
     });
 });
 
 // Convert encoding streaming example
-fs.createReadStream('file-in-win1251.txt')
-    .pipe(iconv.decodeStream('win1251'))
-    .pipe(iconv.encodeStream('ucs2'))
-    .pipe(fs.createWriteStream('file-in-ucs2.txt'));
+fs.createReadStream("file-in-win1251.txt")
+    .pipe(iconv.decodeStream("win1251"))
+    .pipe(iconv.encodeStream("ucs2"))
+    .pipe(fs.createWriteStream("file-in-ucs2.txt"));
 
 // Sugar: all encode/decode streams have .collect(cb) method to accumulate data.
-http.createServer(function(req, res) {
-    req.pipe(iconv.decodeStream('win1251')).collect(function(err, body) {
-        assert(typeof body == 'string');
+http.createServer(function (req, res) {
+    req.pipe(iconv.decodeStream("win1251")).collect(function (err, body) {
+        assert(typeof body == "string");
         console.log(body); // full request body string
     });
 });
 ```
 
 ## Supported encodings
 
- *  All node.js native encodings: utf8, ucs2 / utf16-le, ascii, binary, base64, hex.
- *  Additional unicode encodings: utf16, utf16-be, utf-7, utf-7-imap, utf32, utf32-le, and utf32-be.
- *  All widespread singlebyte encodings: Windows 125x family, ISO-8859 family, 
-    IBM/DOS codepages, Macintosh family, KOI8 family, all others supported by iconv library. 
+-   All node.js native encodings: utf8, ucs2 / utf16-le, ascii, binary, base64, hex.
+-   Additional unicode encodings: utf16, utf16-be, utf-7, utf-7-imap, utf32, utf32-le, and utf32-be.
+-   All widespread singlebyte encodings: Windows 125x family, ISO-8859 family,
+    IBM/DOS codepages, Macintosh family, KOI8 family, all others supported by iconv library.
     Aliases like 'latin1', 'us-ascii' also supported.
- *  All widespread multibyte encodings: CP932, CP936, CP949, CP950, GB2312, GBK, GB18030, Big5, Shift_JIS, EUC-JP.
+-   All widespread multibyte encodings: CP932, CP936, CP949, CP950, GB2312, GBK, GB18030, Big5, Shift_JIS, EUC-JP.
 
 See [all supported encodings on wiki](https://github.com/ashtuchkin/iconv-lite/wiki/Supported-Encodings).
 
 Most singlebyte encodings are generated automatically from [node-iconv](https://github.com/bnoordhuis/node-iconv). Thank you Ben Noordhuis and libiconv authors!
 
 Multibyte encodings are generated from [Unicode.org mappings](http://www.unicode.org/Public/MAPPINGS/) and [WHATWG Encoding Standard mappings](http://encoding.spec.whatwg.org/). Thank you, respective authors!
 
-
 ## Encoding/decoding speed
 
-Comparison with node-iconv module (1000x256kb, on MacBook Pro, Core i5/2.6 GHz, Node v0.12.0). 
+Comparison with node-iconv module (1000x256kb, on MacBook Pro, Core i5/2.6 GHz, Node v0.12.0).
 Note: your results may vary, so please always check on your hardware.
 
     operation             [email protected]   [email protected]
@@ -87,31 +112,33 @@ Note: your results may vary, so please always check on your hardware.
 
 ## BOM handling
 
- * Decoding: BOM is stripped by default, unless overridden by passing `stripBOM: false` in options
-   (f.ex. `iconv.decode(buf, enc, {stripBOM: false})`).
-   A callback might also be given as a `stripBOM` parameter - it'll be called if BOM character was actually found.
- * If you want to detect UTF-8 BOM when decoding other encodings, use [node-autodetect-decoder-stream](https://github.com/danielgindi/node-autodetect-decoder-stream) module.
- * Encoding: No BOM added, unless overridden by `addBOM: true` option.
+-   Decoding: BOM is stripped by default, unless overridden by passing `stripBOM: false` in options
+    (f.ex. `iconv.decode(buf, enc, {stripBOM: false})`).
+    A callback might also be given as a `stripBOM` parameter - it'll be called if BOM character was actually found.
+-   If you want to detect UTF-8 BOM when decoding other encodings, use [node-autodetect-decoder-stream](https://github.com/danielgindi/node-autodetect-decoder-stream) module.
+-   Encoding: No BOM added, unless overridden by `addBOM: true` option.
 
 ## UTF-16 Encodings
 
 This library supports UTF-16LE, UTF-16BE and UTF-16 encodings. First two are straightforward, but UTF-16 is trying to be
 smart about endianness in the following ways:
- * Decoding: uses BOM and 'spaces heuristic' to determine input endianness. Default is UTF-16LE, but can be 
-   overridden with `defaultEncoding: 'utf-16be'` option. Strips BOM unless `stripBOM: false`.
- * Encoding: uses UTF-16LE and writes BOM by default. Use `addBOM: false` to override.
+
+-   Decoding: uses BOM and 'spaces heuristic' to determine input endianness. Default is UTF-16LE, but can be
+    overridden with `defaultEncoding: 'utf-16be'` option. Strips BOM unless `stripBOM: false`.
+-   Encoding: uses UTF-16LE and writes BOM by default. Use `addBOM: false` to override.
 
 ## UTF-32 Encodings
 
-This library supports UTF-32LE, UTF-32BE and UTF-32 encodings. Like the UTF-16 encoding above, UTF-32 defaults to UTF-32LE, but uses BOM and 'spaces heuristics' to determine input endianness. 
- * The default of UTF-32LE can be overridden with the `defaultEncoding: 'utf-32be'` option. Strips BOM unless `stripBOM: false`.
- * Encoding: uses UTF-32LE and writes BOM by default. Use `addBOM: false` to override. (`defaultEncoding: 'utf-32be'` can also be used here to change encoding.)
+This library supports UTF-32LE, UTF-32BE and UTF-32 encodings. Like the UTF-16 encoding above, UTF-32 defaults to UTF-32LE, but uses BOM and 'spaces heuristics' to determine input endianness.
+
+-   The default of UTF-32LE can be overridden with the `defaultEncoding: 'utf-32be'` option. Strips BOM unless `stripBOM: false`.
+-   Encoding: uses UTF-32LE and writes BOM by default. Use `addBOM: false` to override. (`defaultEncoding: 'utf-32be'` can also be used here to change encoding.)
 
 ## Other notes
 
-When decoding, be sure to supply a Buffer to decode() method, otherwise [bad things usually happen](https://github.com/ashtuchkin/iconv-lite/wiki/Use-Buffers-when-decoding).  
-Untranslatable characters are set to � or ?. No transliteration is currently supported.  
-Node versions 0.10.31 and 0.11.13 are buggy, don't use them (see #65, #77).  
+-   When decoding, be sure to supply a Buffer to decode() method, otherwise [bad things usually happen](https://github.com/ashtuchkin/iconv-lite/wiki/Use-Buffers-when-decoding).
+-   Untranslatable characters are set to � or ?. No transliteration is currently supported.
+-   Node versions 0.10.31 and 0.11.13 are buggy, don't use them (see #65, #77).
 
 ## Testing
 
@@ -120,7 +147,7 @@ $ git clone [email protected]:ashtuchkin/iconv-lite.git
 $ cd iconv-lite
 $ npm install
 $ npm test
-    
+
 $ # To view performance:
 $ node test/performance.js