dom-compare

dom-compare
===========


NodeJS module to compare two DOM-trees

* DOM Comparison
* Comparison options
* Comments comparison
* Whitespace comparison
* Cli utility
* DOM Canonic Form

Works with Node.JS v0.10+

DOM Comparison
--------------

Consider two documents. Expected:
``xml



text content






`
and actual one:
`xml


text content





`

One can compare them, get the result (is them equals, or not), and get extended report (why them are different).

`javascript
var compare = require('dom-compare').compare,
reporter = require('dom-compare').GroupingReporter,
expected = ..., // expected DOM tree
actual = ..., // actual one
result, diff, groupedDiff;

// compare to DOM trees, get a result object
result = compare(expected, actual);

// get comparison result
console.log(result.getResult()); // false cause' trees are different

// get all differences
diff = result.getDifferences(); // array of diff-objects

// differences, grouped by node XPath
groupedDiff = reporter.getDifferences(result); // object, key - node XPATH, value - array of differences (strings)

// string representation
console.log(reporter.report(result));
`

Diff-object has a following form:

`javascript
{
node: "/document/element",
message: "Attribute 'attribute': expected value '10' instead of '100'";
}
`

By using GroupingReporter one can get a result of a following type

`javascript
{
'/document/element': [
"Attribute 'attribute': expected value '10' instead of '100'",
"Extra attribute 'attributeX'"
]
}
`

$3

Comparison function can take a third argument with options like this:
`javascript
var options = {
stripSpaces: true,
compareComments: true,
collapseSpaces: true,
normalizeNewlines: true
};

result = compare(expected, actual, options);
`
#### Comments comparison
By default, all comments are ignored. Set compareComments options to true to compare them too.


#### Whitespace comparison
By default, all text nodes (text, CDATA, comments if enabled as mentioned above) compared with respect
to leading, trailing, and internal whitespaces.
Set stripSpaces option to true to automatically strip spaces in text and comment nodes. This option
doesn't change the way CDATA sections is compared, they are always compared with respect to whitespaces.
Set collapseSpaces option to true to automatically collapse all spaces in text and comment nodes.
This option doesn't change the way CDATA sections is compared, they are always compared with respect to
whitespaces.
Set normalizeNewlines option to true to automatically normalize new line characters in text,
comment, and CDATA nodes.

$3

When installed globally with npm install -g dom-compare cli utility is available.
See usage information and command-line options with domcompare --help

You can try it on bundled samples:
`
$ cd samples
$ domcompare -s ./expected.xml ./actual.xml
Documents are not equal
/document/element
Attribute 'attribute': expected value '10' instead of '100'
Attribute 'attributeX' is missed
Extra element 'inner2'
/document/element/inner
Element 'node' is missed
/document
Expected CDATA value ' cdata node' instead of 'cdata node '
`


DOM Canonic Form
----------------

Implemented as XMLSerializer interface


Simple rules
1. Every node (text, node, attribute) on a new line
2. Empty tags - in a short form
3. Node indent - 4 spaces, attribute indent - 2 spaces
4. Attributes are sorted alphabetically
5. Attribute values are serialized in double quotes

Consider the following XML-document...
`xml

DOM Compare


Text node


`
...and code snippet...
`javascript
var canonizingSerializer = new (require('dom-compare').XMLSerializer)();
var doc = ...; // parse above document somehow
console.log(canonizingSerializer.serializeToString(doc));
`
You'll receive the following output
`xml


DOM Compare


attribute1="value"
attribute2="value">

Text node



``