add append, appendString, and appendBuffer methods (closes #1)

index.js

@@ -7,10 +7,14 @@
 'use strict';
 
 var os = require('os');
+var equals = require('buffer-equal');
 var normalize = require('normalize-path');
 var stripBOM = require('strip-bom-string');
 var file = module.exports;
 
+file.cr = new Buffer('\r\n');
+file.nl = new Buffer('\n');
+
 /**
  * Normalize slashes in the given filepath to forward slashes.
  * Note that this is a simple replacement of `\\` with `/`, and
@@ -96,3 +100,104 @@ file.stripBOM = function(str) {
   }
   return stripBOM(str);
 };
+
+/**
+ * Append a string or buffer to another string or buffer ensuring to preserve line ending characters.
+ *
+ * ```js
+ * console.log([append(new Buffer('abc\r\n'), new Buffer('def')).toString()]);
+ * //=> [ 'abc\r\ndef\r\n' ]
+ *
+ * console.log([append(new Buffer('abc\n'), new Buffer('def')).toString()]);
+ * //=> [ 'abc\ndef\n' ]
+ *
+ * // uses os.EOL when a line ending is not found
+ * console.log([append(new Buffer('abc'), new Buffer('def')).toString()]);
+ * //=> [ 'abc\ndef' ]
+ *
+ * console.log([append('abc\r\n', 'def')]);
+ * //=> [ 'abc\r\ndef\r\n' ]
+ *
+ * console.log([append('abc\n', 'def')]);
+ * //=> [ 'abc\ndef\n' ]
+ *
+ * // uses os.EOL when a line ending is not found
+ * console.log([append('abc', 'def')]);
+ * //=> [ 'abc\ndef' ]
+ * ```
+ * @param  {String|Buffer} `prefix` String or Buffer that will be used to check for an existing line ending. The suffix is appended to this.
+ * @param  {String|Buffer} `suffix` String or Buffer that will be appended to the prefix.
+ * @return {String|Buffer} Final String or Buffer
+ * @api public
+ */
+
+file.append = function(prefix, suffix) {
+  if (Buffer.isBuffer(prefix)) {
+    return file.appendBuffer(prefix, suffix);
+  }
+  return file.appendString(prefix, suffix);
+};
+
+/**
+ * Append a string to another string ensuring to preserve line ending characters.
+ *
+ * ```js
+ * console.log([appendString('abc\r\n', 'def')]);
+ * //=> [ 'abc\r\ndef\r\n' ]
+ *
+ * console.log([appendString('abc\n', 'def')]);
+ * //=> [ 'abc\ndef\n' ]
+ *
+ * // uses os.EOL when a line ending is not found
+ * console.log([appendString('abc', 'def')]);
+ * //=> [ 'abc\ndef' ]
+ * ```
+ * @param  {String} `str` String that will be used to check for an existing line ending. The suffix is appended to this.
+ * @param  {String} `suffix` String that will be appended to the str.
+ * @return {String} Final String
+ * @api public
+ */
+
+file.appendString = function(str, suffix) {
+  var eol;
+  if (str.slice(-2) === '\r\n') {
+    eol = '\r\n';
+  } else if (str.slice(-1) === '\n') {
+    eol = '\n';
+  } else {
+    return [str, os.EOL, suffix].join('');
+  }
+  return [str, suffix, eol].join('');
+};
+
+/**
+ * Append a buffer to another buffer ensuring to preserve line ending characters.
+ *
+ * ```js
+ * console.log([appendBuffer(new Buffer('abc\r\n'), new Buffer('def')).toString()]);
+ * //=> [ 'abc\r\ndef\r\n' ]
+ *
+ * console.log([appendBuffer(new Buffer('abc\n'), new Buffer('def')).toString()]);
+ * //=> [ 'abc\ndef\n' ]
+ *
+ * // uses os.EOL when a line ending is not found
+ * console.log([appendBuffer(new Buffer('abc'), new Buffer('def')).toString()]);
+ * //=> [ 'abc\ndef' ]
+ * * ```
+ * @param  {Buffer} `buf` Buffer that will be used to check for an existing line ending. The suffix is appended to this.
+ * @param  {Buffer} `suffix` Buffer that will be appended to the buf.
+ * @return {Buffer} Final Buffer
+ * @api public
+ */
+
+file.appendBuffer = function(buf, suffix) {
+  var eol;
+  if (equals(buf.slice(-2), file.cr)) {
+    eol = file.cr;
+  } else if (equals(buf.slice(-1), file.nl)) {
+    eol = file.nl;
+  } else {
+    return Buffer.concat([buf, new Buffer(os.EOL), new Buffer(suffix)]);
+  }
+  return Buffer.concat([buf, new Buffer(suffix), eol]);
+};

package.json

@@ -20,6 +20,7 @@
     "test": "mocha"
   },
   "dependencies": {
+    "buffer-equal": "^1.0.0",
     "normalize-path": "^2.0.1",
     "strip-bom-string": "^0.1.2"
   },
@@ -61,4 +62,4 @@
       "reflinks": true
     }
   }
-}
+}

test.js

@@ -24,13 +24,115 @@ describe('file-normalize', function() {
   });
 
   it('should normalize EOL to unix newlines', function() {
-    assert.equal(file.normalizeEOL('foo\r\nbar'), 'foo\nbar');
-    assert.equal(file.normalizeEOL('foo\r\n\r\nbar'), 'foo\n\nbar');
-    assert.equal(file.normalizeEOL('foo\rbar'), 'foo\nbar');
-    assert.equal(file.normalizeEOL('foo\nbar'), 'foo\nbar');
+    assert.equal(file.normalizeEOL('foo\r\nbar', '\n'), 'foo\nbar');
+    assert.equal(file.normalizeEOL('foo\r\n\r\nbar', '\n'), 'foo\n\nbar');
+    assert.equal(file.normalizeEOL('foo\rbar', '\n'), 'foo\nbar');
+    assert.equal(file.normalizeEOL('foo\nbar', '\n'), 'foo\nbar');
   });
 
   it('should strip byte-order marks', function() {
     assert.equal(file.stripBOM('\ufefffoo\nbar'), 'foo\nbar');
   });
+
+  describe('appendBuffer', function() {
+    it('should append the buffer suffix to the buffer prefix with \\r\\n', function() {
+      assert.deepEqual(file.appendBuffer(new Buffer('abc\r\n'), new Buffer('def')), new Buffer('abc\r\ndef\r\n'));
+    });
+
+    it('should append the buffer suffix to the buffer prefix with \\n:', function() {
+      assert.deepEqual(file.appendBuffer(new Buffer('abc\n'), new Buffer('def')), new Buffer('abc\ndef\n'));
+    });
+
+    it('should append the buffer suffix to the buffer prefix without EOL', function() {
+      assert.deepEqual(file.appendBuffer(new Buffer('abc'), new Buffer('def')), new Buffer('abc' + os.EOL + 'def'));
+    });
+
+    it('should append the string suffix to the buffer prefix with \\r\\n', function() {
+      assert.deepEqual(file.appendBuffer(new Buffer('abc\r\n'), 'def'), new Buffer('abc\r\ndef\r\n'));
+    });
+
+    it('should append the string suffix to the buffer prefix with \\n:', function() {
+      assert.deepEqual(file.appendBuffer(new Buffer('abc\n'), 'def'), new Buffer('abc\ndef\n'));
+    });
+
+    it('should append the string suffix to the buffer prefix without EOL', function() {
+      assert.deepEqual(file.appendBuffer(new Buffer('abc'), 'def'), new Buffer('abc' + os.EOL + 'def'));
+    });
+  });
+
+  describe('appendString', function() {
+    it('should append the string suffix to the string prefix with \\r\\n', function() {
+      assert.equal(file.appendString('abc\r\n', 'def'), 'abc\r\ndef\r\n');
+    });
+
+    it('should append the string suffix to the string prefix with \\n:', function() {
+      assert.equal(file.appendString('abc\n', 'def'), 'abc\ndef\n');
+    });
+
+    it('should append the string suffix to the string prefix without EOL', function() {
+      assert.equal(file.appendString('abc', 'def'), 'abc' + os.EOL + 'def');
+    });
+
+    it('should append the buffer suffix to the string prefix with \\r\\n', function() {
+      assert.equal(file.appendString('abc\r\n', new Buffer('def')), 'abc\r\ndef\r\n');
+    });
+
+    it('should append the buffer suffix to the string prefix with \\n:', function() {
+      assert.equal(file.appendString('abc\n', new Buffer('def')), 'abc\ndef\n');
+    });
+
+    it('should append the buffer suffix to the string prefix without EOL', function() {
+      assert.equal(file.appendString('abc', new Buffer('def')), 'abc' + os.EOL + 'def');
+    });
+  });
+
+  describe('append', function() {
+    it('should append the buffer suffix to the buffer prefix with \\r\\n', function() {
+      assert.deepEqual(file.append(new Buffer('abc\r\n'), new Buffer('def')), new Buffer('abc\r\ndef\r\n'));
+    });
+
+    it('should append the buffer suffix to the buffer prefix with \\n:', function() {
+      assert.deepEqual(file.append(new Buffer('abc\n'), new Buffer('def')), new Buffer('abc\ndef\n'));
+    });
+
+    it('should append the buffer suffix to the buffer prefix without EOL', function() {
+      assert.deepEqual(file.append(new Buffer('abc'), new Buffer('def')), new Buffer('abc' + os.EOL + 'def'));
+    });
+
+    it('should append the string suffix to the string prefix with \\r\\n', function() {
+      assert.equal(file.append('abc\r\n', 'def'), 'abc\r\ndef\r\n');
+    });
+
+    it('should append the string suffix to the string prefix with \\n:', function() {
+      assert.equal(file.append('abc\n', 'def'), 'abc\ndef\n');
+    });
+
+    it('should append the string suffix to the string prefix without EOL', function() {
+      assert.equal(file.append('abc', 'def'), 'abc' + os.EOL + 'def');
+    });
+
+    it('should append the string suffix to the buffer prefix with \\r\\n', function() {
+      assert.deepEqual(file.append(new Buffer('abc\r\n'), 'def'), new Buffer('abc\r\ndef\r\n'));
+    });
+
+    it('should append the string suffix to the buffer prefix with \\n:', function() {
+      assert.deepEqual(file.append(new Buffer('abc\n'), 'def'), new Buffer('abc\ndef\n'));
+    });
+
+    it('should append the string suffix to the buffer prefix without EOL', function() {
+      assert.deepEqual(file.append(new Buffer('abc'), 'def'), new Buffer('abc' + os.EOL + 'def'));
+    });
+
+    it('should append the buffer suffix to the string prefix with \\r\\n', function() {
+      assert.equal(file.append('abc\r\n', new Buffer('def')), 'abc\r\ndef\r\n');
+    });
+
+    it('should append the buffer suffix to the string prefix with \\n:', function() {
+      assert.equal(file.append('abc\n', new Buffer('def')), 'abc\ndef\n');
+    });
+
+    it('should append the buffer suffix to the string prefix without EOL', function() {
+      assert.equal(file.append('abc', new Buffer('def')), 'abc' + os.EOL + 'def');
+    });
+  });
 });