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Adding Diff Trimmed Lines #47

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merged 4 commits into from
Mar 1, 2015
Merged

Adding Diff Trimmed Lines #47

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3ac9cb4
Adding Diff Trimmed Lines
Feb 9, 2015
1892d77
Documentation and tests for TrimmedLineDiff
Feb 11, 2015
b8cd87f
Fixing windows new line merge and readme
Feb 12, 2015
cb0c827
Style, nitpick, and word choice
Feb 19, 2015
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5 changes: 4 additions & 1 deletion README.md
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Original file line number Diff line number Diff line change
Expand Up @@ -33,6 +33,10 @@ or

Returns a list of change objects (See below).

* `JsDiff.diffTrimmedLines(oldStr, newStr[, callback])` - diffs two blocks of text, comparing line by line, ignoring leading and trailing whitespace.

Returns a list of change objects (See below).

* `JsDiff.diffSentences(oldStr, newStr[, callback])` - diffs two blocks of text, comparing sentence by sentence.

Returns a list of change objects (See below).
Expand Down Expand Up @@ -166,4 +170,3 @@ OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.


[![Bitdeli Badge](https://d2weczhvl823v0.cloudfront.net/kpdecker/jsdiff/trend.png)](https://bitdeli.com/free "Bitdeli Badge")

46 changes: 33 additions & 13 deletions diff.js
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Expand Up @@ -15,6 +15,7 @@
* http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.4.6927
*/
(function(global, undefined) {

var JsDiff = (function() {
/*jshint maxparams: 5*/
/*istanbul ignore next*/
Expand Down Expand Up @@ -174,7 +175,7 @@
editLength++;
}

// Performs the length of edit iteration. Is a bit fugly as this has to support the
// Performs the length of edit iteration. Is a bit fugly as this has to support the
// sync and async mode which is never fun. Loops over execEditLength until a value
// is produced.
var editLength = 1;
Expand Down Expand Up @@ -256,25 +257,42 @@
};

var LineDiff = new Diff();
LineDiff.tokenize = function(value) {

var TrimmedLineDiff = new Diff();
TrimmedLineDiff.ignoreTrim = true;

LineDiff.tokenize = TrimmedLineDiff.tokenize = function(value) {
var retLines = [],
lines = value.split(/^/m);

for(var i = 0; i < lines.length; i++) {
var line = lines[i],
lastLine = lines[i - 1];
lastLine = lines[i - 1],
lastLineLastChar = lastLine ? lastLine[lastLine.length - 1] : '';

// Merge lines that may contain windows new lines
if (line === '\n' && lastLine && lastLine[lastLine.length - 1] === '\r') {
retLines[retLines.length - 1] += '\n';
if (line === '\n' && (lastLineLastChar === '\r' || lastLineLastChar === '\n')) {
if (this.ignoreTrim || lastLineLastChar === '\n'){
//to avoid merging to \n\n, remove \n and add \r\n.
retLines[retLines.length - 1] = retLines[retLines.length - 1].slice(0,-1) + '\r\n';
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Why is this \r\n here but \n below?

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string.trim() in JS removes the newline characters, which puts the entire diff on one line, so I added the '\n' character after trimming every line but the last line. However, then when it tried to merge empty lines using:

retLines[retLines.length - 1] += '\n';

It would end up with '\n\n' on the end of the line, instead of '\r\n' I fixed this by slicing and re-adding the '\r\n'.

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I don't think we should use \r\n here. We are normalizing it to \n for all other lines so it's surprising to have it here and nowhere else. Instead, I would do nothing. I.e.

if (line === '\n' && lastLine && lastLine[lastLine.length - 1] === '\r') {
  if (!this.ignoreTrim) {
    retLines[retLines.length - 1] += '\n';
  }
}

We can do this because we know that the line will always have a \n at the end due to the += operation below.

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This causes the tests I wrote to fail, which isn't necessarily a problem, but I followed the test set by the Line Diff tests, so I don't think it is exhibiting different behavior that that.

The final Line Diff test is:

it('should handle windows line endings', function() {
    var diffResult = diff.diffLines(
      'line\r\nold value \r\nline',
      'line\r\nnew value\r\nline');
    diff.convertChangesToXML(diffResult).should.equal('line\r\nnew value\r\nold value \r\nline');
  });

The final Trimmed Line Diff test is:

  it('should handle windows line endings', function() {
    var diffResult = diff.diffTrimmedLines(
      'line\r\nold value \r\nline',
      'line\r\nnew value\r\nline');
    diff.convertChangesToXML(diffResult).should.equal('line\r\nnew value\r\nold value\r\nline');
  });

Changing to your suggested code causes the second test to fail with the following value (no \r):

'line\n<ins>new value\n</ins><del>old value\n</del>line'

This is the only thing I'm not sure about, everything else should be updated in my most recent commit.

} else {
retLines[retLines.length - 1] += '\n';
}
} else if (line) {
if (this.ignoreTrim) {
line = line.trim();
//add a newline unless this is the last line.
if (i < lines.length - 1) {
line += '\n';
}
}
retLines.push(line);
}
}

return retLines;
};


var SentenceDiff = new Diff();
SentenceDiff.tokenize = function (value) {
return removeEmpty(value.split(/(\S.+?[.!?])(?=\s+|$)/));
Expand Down Expand Up @@ -344,6 +362,8 @@
diffWords: function(oldStr, newStr, callback) { return WordDiff.diff(oldStr, newStr, callback); },
diffWordsWithSpace: function(oldStr, newStr, callback) { return WordWithSpaceDiff.diff(oldStr, newStr, callback); },
diffLines: function(oldStr, newStr, callback) { return LineDiff.diff(oldStr, newStr, callback); },
diffTrimmedLines: function(oldStr, newStr, callback) { return TrimmedLineDiff.diff(oldStr, newStr, callback); },

diffSentences: function(oldStr, newStr, callback) { return SentenceDiff.diff(oldStr, newStr, callback); },

diffCss: function(oldStr, newStr, callback) { return CssDiff.diff(oldStr, newStr, callback); },
Expand Down Expand Up @@ -447,7 +467,7 @@
addEOFNL = false;

for (var i = (diffstr[0][0]==='I'?4:0); i < diffstr.length; i++) {
if(diffstr[i][0] === '@') {
if (diffstr[i][0] === '@') {
var meh = diffstr[i].split(/@@ -(\d+),(\d+) \+(\d+),(\d+) @@/);
diff.unshift({
start:meh[3],
Expand All @@ -456,17 +476,17 @@
newlength:meh[4],
newlines:[]
});
} else if(diffstr[i][0] === '+') {
} else if (diffstr[i][0] === '+') {
diff[0].newlines.push(diffstr[i].substr(1));
} else if(diffstr[i][0] === '-') {
} else if (diffstr[i][0] === '-') {
diff[0].oldlines.push(diffstr[i].substr(1));
} else if(diffstr[i][0] === ' ') {
} else if (diffstr[i][0] === ' ') {
diff[0].newlines.push(diffstr[i].substr(1));
diff[0].oldlines.push(diffstr[i].substr(1));
} else if(diffstr[i][0] === '\\') {
} else if (diffstr[i][0] === '\\') {
if (diffstr[i-1][0] === '+') {
remEOFNL = true;
} else if(diffstr[i-1][0] === '-') {
} else if (diffstr[i-1][0] === '-') {
addEOFNL = true;
}
}
Expand All @@ -476,7 +496,7 @@
for (var i = diff.length - 1; i >= 0; i--) {
var d = diff[i];
for (var j = 0; j < d.oldlength; j++) {
if(str[d.start-1+j] !== d.oldlines[j]) {
if (str[d.start-1+j] !== d.oldlines[j]) {
return false;
}
}
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1 change: 1 addition & 0 deletions index.html
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Expand Up @@ -11,6 +11,7 @@ <h1>Diff</h1>
<label><input type="radio" name="diff_type" value="diffChars" checked> Chars</label>
<label><input type="radio" name="diff_type" value="diffWords"> Words</label>
<label><input type="radio" name="diff_type" value="diffLines"> Lines</label>
<label><input type="radio" name="diff_type" value="diffTrimmedLines"> Trimmed Lines</label>
<label><input type="radio" name="diff_type" value="createPatch"> Patch</label>
<label><input type="radio" name="diff_type" value="applyPatch"> Merge</label>
</div>
Expand Down
32 changes: 31 additions & 1 deletion test/diffTest.js
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Expand Up @@ -185,7 +185,7 @@ describe('#diffLines', function() {
diff.convertChangesToXML(diffResult).should.equal('line\nvalue\nline');
});

it('should handle shorespace', function() {
it('should handle leading and trailing whitespace', function() {
var diffResult = diff.diffLines(
'line\nvalue \nline',
'line\nvalue\nline');
Expand All @@ -200,6 +200,36 @@ describe('#diffLines', function() {
});
});

// Trimmed Line Diff
describe('#TrimmedLineDiff', function() {
it('should diff lines', function() {
var diffResult = diff.diffTrimmedLines(
'line\nold value\nline',
'line\nnew value\nline');
diff.convertChangesToXML(diffResult).should.equal('line\n<ins>new value\n</ins><del>old value\n</del>line');
});
it('should the same lines in diff', function() {
var diffResult = diff.diffTrimmedLines(
'line\nvalue\nline',
'line\nvalue\nline');
diff.convertChangesToXML(diffResult).should.equal('line\nvalue\nline');
});

it('should ignore leading and trailing whitespace', function() {
var diffResult = diff.diffTrimmedLines(
'line\nvalue \nline',
'line\nvalue\nline');
diff.convertChangesToXML(diffResult).should.equal('line\nvalue\nline');
});

it('should handle windows line endings', function() {
var diffResult = diff.diffTrimmedLines(
'line\r\nold value \r\nline',
'line\r\nnew value\r\nline');
diff.convertChangesToXML(diffResult).should.equal('line\r\n<ins>new value\r\n</ins><del>old value\r\n</del>line');
});
});

describe('#diffJson', function() {
it('should accept objects', function() {
diff.diffJson(
Expand Down