Add option for trimming CR at the end of a line

README.md

@@ -18,6 +18,7 @@ Install with
 * `options` - Object
   * `readChunk` - Integer number of bytes to read at once. Default: 1024
   * `newLineCharacter` - String new line character, only works with one byte characters for now. Default: `\n` which is `0x0a` hex encoded
+  * `lineTrimCR` bool - If set to true, carriege return character - `0x0d` will be trimmed if found at the end of a line. Default: false
 
 `node-readlines` can handle files without newLineCharacter after the last line
 

readlines.js

@@ -11,6 +11,9 @@ class LineByLine {
 
         if (!options.readChunk) options.readChunk = 1024;
 
+        // Trim carriege return CR 0x0D if found at the end of a line.
+        if (!options.lineTrimCR) options.lineTrimCR = false;
+
         if (!options.newLineCharacter) {
             options.newLineCharacter = 0x0a; //linux line ending
         } else {
@@ -26,6 +29,7 @@ class LineByLine {
         this.options = options;
 
         this.newLineCharacter = options.newLineCharacter;
+        this.crCharacter = 0x0d;
 
         this.reset();
     }
@@ -152,6 +156,10 @@ class LineByLine {
             line = line.slice(0, line.length-1);
         }
 
+        if (this.options.lineTrimCR === true && line && line[line.length-1] === this.crCharacter) {
+            line = line.slice(0, line.length-1);
+        }
+
         return line;
     }
 }

test/fixtures/linesWithCR.txt

@@ -0,0 +1,3 @@
+line1here
+line2here
+line3here

test/readlines.test.js

@@ -88,7 +88,6 @@ test('should reset and start from the beggining', (t) => {
 
 test('should read big lines', (t) => {
     const liner = new lineByLine(path.resolve(__dirname, 'fixtures/bigLines.json'));
-
 
     t.ok(JSON.parse(liner.next()), 'line 0: valid JSON');
     t.ok(JSON.parse(liner.next()), 'line 1: valid JSON');
@@ -130,3 +129,27 @@ test('should correctly processes NULL character in lines', (t) => {
     t.equals(liner.fd, null, 'fd is null');
     t.end();
 })
+
+test('should NOT trim CR characters at the end of the line', (t) => {
+    const liner = new lineByLine(path.resolve(__dirname, 'fixtures/linesWithCR.txt'));
+
+    t.equals(liner.next().toString(), 'line1here\r');
+    t.equals(liner.next().toString(), 'line2here\r');
+    t.equals(liner.next().toString(), 'line3here\r');
+
+    t.equals(liner.fd, null, 'fd is null');
+    t.end();
+})
+
+test('should trim CR characters at the end of the line', (t) => {
+    const liner = new lineByLine(path.resolve(__dirname, 'fixtures/linesWithCR.txt'), {
+        'lineTrimCR': true
+    });
+
+    t.equals(liner.next().toString(), 'line1here');
+    t.equals(liner.next().toString(), 'line2here');
+    t.equals(liner.next().toString(), 'line3here');
+
+    t.equals(liner.fd, null, 'fd is null');
+    t.end();
+})