v1.1.0

Author: andris9

.eslintrc

@@ -1,3 +1,11 @@
 {
-    "extends":    "nodemailer"
+    "rules": {
+        "indent": 0,
+        "global-require": 0,
+        "no-await-in-loop": 0
+    },
+    "extends": ["nodemailer", "prettier"],
+    "parserOptions": {
+        "ecmaVersion": 2017
+    }
 }

.prettierrc.js

@@ -0,0 +1,5 @@
+module.exports = {
+    printWidth: 160,
+    tabWidth: 4,
+    singleQuote: true
+};

README.md

@@ -22,7 +22,7 @@ Encode Buffer objects or unicode strings with
 
 Where
 
-* **val** is a Buffer or an unicode string
+-   **val** is a Buffer or an unicode string
 
 **Example**
 
@@ -39,8 +39,8 @@ To enforce soft line breaks on lines longer than selected amount of characters,
 
 Where
 
-* **str** is a base64 encoded string
-* **lineLength** (defaults to 76) is the maximum allowed line length
+-   **str** is a base64 encoded string
+-   **lineLength** (defaults to 76) is the maximum allowed line length
 
 **Example**
 
@@ -63,8 +63,11 @@ Create new Encoder Stream with
 
 Where
 
-* **options** is the optional stream options object with an additional option `lineLength` if you want to use any other line length than the default 76
-  characters (or set to `false` to turn the soft wrapping off completely)
+-   **options** is the optional stream options object
+-   **options.lineLength** (Number) if you want to use any other line length than the default 76
+    characters (or set to `false` to turn the soft wrapping off completely)
+-   **options.skipStartBytes** (Number) Optional. How many bytes to skip from output (default to 0)
+-   **options.limitOutbutBytes** (Number) Optional. How many bytes to return (defaults to all bytes)
 
 **Example**
 
@@ -88,7 +91,7 @@ Create new Decoder Stream with
 
 Where
 
-* **options** is the optional stream options object
+-   **options** is the optional stream options object
 
 **Example**
 

lib/libbase64.js

@@ -68,21 +68,50 @@ function wrap(str, lineLength) {
 class Encoder extends Transform {
     constructor(options) {
         super();
-
         // init Transform
         this.options = options || {};
 
         if (this.options.lineLength !== false) {
             this.options.lineLength = this.options.lineLength || 76;
         }
 
+        this.skipStartBytes = this.options.skipStartBytes || 0;
+        this.limitOutbutBytes = this.options.limitOutbutBytes || 0;
+
         this._curLine = '';
         this._remainingBytes = false;
 
         this.inputBytes = 0;
         this.outputBytes = 0;
     }
 
+    _writeChunk(chunk /*, isFinal */) {
+        if (this.skipStartBytes) {
+            if (chunk.length <= this.skipStartBytes) {
+                this.skipStartBytes -= chunk.length;
+                return;
+            }
+
+            chunk = chunk.slice(this.skipStartBytes);
+            this.skipStartBytes = 0;
+        }
+
+        if (this.limitOutbutBytes) {
+            if (this.outputBytes + chunk.length <= this.limitOutbutBytes) {
+                // ignore, can use entire chunk
+            } else if (this.outputBytes >= this.limitOutbutBytes) {
+                // chunks already processed
+                return;
+            } else {
+                // use partial chunk
+                chunk = chunk.slice(0, this.limitOutbutBytes - this.outputBytes);
+            }
+        }
+
+        this.outputBytes += chunk.length;
+        this.push(chunk);
+    }
+
     _transform(chunk, encoding, done) {
         if (encoding !== 'buffer') {
             chunk = Buffer.from(chunk, encoding);
@@ -100,8 +129,8 @@ class Encoder extends Transform {
         }
 
         if (chunk.length % 3) {
-            this._remainingBytes = chunk.slice(chunk.length - chunk.length % 3);
-            chunk = chunk.slice(0, chunk.length - chunk.length % 3);
+            this._remainingBytes = chunk.slice(chunk.length - (chunk.length % 3));
+            chunk = chunk.slice(0, chunk.length - (chunk.length % 3));
         } else {
             this._remainingBytes = false;
         }
@@ -125,8 +154,7 @@ class Encoder extends Transform {
         }
 
         if (b64) {
-            this.outputBytes += b64.length;
-            this.push(Buffer.from(b64, 'ascii'));
+            this._writeChunk(Buffer.from(b64, 'ascii'), false);
         }
 
         setImmediate(done);
@@ -136,13 +164,13 @@ class Encoder extends Transform {
         if (this._remainingBytes && this._remainingBytes.length) {
             this._curLine += encode(this._remainingBytes);
         }
+
         if (this._curLine) {
             this._curLine = wrap(this._curLine, this.options.lineLength);
-            this.outputBytes += this._curLine.length;
-            this.push(Buffer.from(this._curLine, 'ascii'));
+            this._writeChunk(Buffer.from(this._curLine, 'ascii'), true);
             this._curLine = '';
         }
-        setImmediate(done);
+        done();
     }
 }
 

package.json

@@ -1,6 +1,6 @@
 {
     "name": "libbase64",
-    "version": "1.0.3",
+    "version": "1.1.0",
     "description": "Encode and decode base64 encoded strings",
     "main": "lib/libbase64.js",
     "scripts": {
@@ -21,13 +21,14 @@
     },
     "homepage": "https://github.com/nodemailer/libbase64",
     "devDependencies": {
-        "chai": "^4.1.2",
+        "chai": "^4.2.0",
         "eslint-config-nodemailer": "^1.2.0",
-        "grunt": "^1.0.3",
-        "grunt-cli": "^1.2.0",
-        "grunt-eslint": "^21.0.0",
+        "eslint-config-prettier": "^6.0.0",
+        "grunt": "^1.0.4",
+        "grunt-cli": "^1.3.2",
+        "grunt-eslint": "^22.0.0",
         "grunt-mocha-test": "^0.13.3",
-        "mocha": "^5.2.0"
+        "mocha": "^6.2.0"
     },
     "dependencies": {}
 }