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A JavaScript Implementation of TreeWalker
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var NodeFilter = { | |
FILTER_ACCEPT: 1, | |
FILTER_REJECT: 2, | |
FILTER_SKIP: 3, | |
SHOW_ALL: -1, | |
SHOW_ELEMENT: 1, | |
SHOW_ATTRIBUTE: 2, | |
SHOW_TEXT: 4, | |
SHOW_CDATA_SECTION: 8, | |
SHOW_ENTITY_REFERENCE: 16, | |
SHOW_ENTITY: 32, | |
SHOW_PROCESSING_INSTRUCTIONS: 64, | |
SHOW_COMMENT: 128, | |
SHOW_DOCUMENT: 256, | |
SHOW_DOCUMENT_TYPE: 512, | |
SHOW_DOCUMENT_FRAGMENT: 1024, | |
SHOW_NOTATION: 2048 | |
}; | |
var TreeWalker = function (root, whatToShow, filter, expandEntityReferences) { | |
this.root = root; | |
this.whatToShow = whatToShow; | |
this.filter = filter; | |
this.expandEntityReferences = expandEntityReferences; | |
this.currentNode = root; | |
this.NodeFilter = NodeFilter; | |
}; | |
TreeWalker.prototype.parentNode = function () { | |
var testNode = this.currentNode; | |
do { | |
if ( | |
testNode !== this.root && | |
testNode.parentNode && | |
testNode.parentNode !== this.root | |
) { | |
testNode = testNode.parentNode; | |
} else { | |
return null; | |
} | |
} while (this._getFilteredStatus(testNode) !== this.NodeFilter.FILTER_ACCEPT); | |
(testNode) && (this.currentNode = testNode); | |
return testNode; | |
}; | |
TreeWalker.prototype.firstChild = function () { | |
var testNode = this.currentNode.firstChild; | |
while(testNode) { | |
if(this._getFilteredStatus(testNode) === this.NodeFilter.FILTER_ACCEPT) { | |
break; | |
} | |
testNode = testNode.nextSibling; | |
} | |
(testNode) && (this.currentNode = testNode); | |
return testNode; | |
}; | |
TreeWalker.prototype.lastChild = function () { | |
var testNode = this.currentNode.lastChild; | |
while (testNode) { | |
if(this._getFilteredStatus(testNode) === this.NodeFilter.FILTER_ACCEPT) { | |
break; | |
} | |
testNode = testNode.previousSibling; | |
} | |
(testNode) && (this.currentNode = testNode); | |
return testNode; | |
}; | |
TreeWalker.prototype.nextNode = function () { | |
var testNode = this.currentNode; | |
while (testNode) { | |
if (testNode.childNodes.length !== 0) { | |
testNode = testNode.firstChild; | |
} else if (testNode.nextSibling) { | |
testNode = testNode.nextSibling; | |
} else { | |
while (testNode) { | |
if (testNode.parentNode && testNode.parentNode !== this.root) { | |
if (testNode.parentNode.nextSibling) { | |
testNode = testNode.parentNode.nextSibling; | |
break; | |
} else { | |
testNode = testNode.parentNode; | |
} | |
} | |
else return null; | |
} | |
} | |
if (testNode && this._getFilteredStatus(testNode) === this.NodeFilter.FILTER_ACCEPT) { | |
break; | |
} | |
} | |
(testNode) && (this.currentNode = testNode); | |
return testNode; | |
}; | |
TreeWalker.prototype.previousNode = function () { | |
var testNode = this.currentNode; | |
while (testNode) { | |
if (testNode.previousSibling) { | |
testNode = testNode.previousSibling; | |
while (testNode.lastChild) { | |
testNode = testNode.lastChild; | |
} | |
} | |
else { | |
if (testNode.parentNode && testNode.parentNode !== this.root) { | |
testNode = testNode.parentNode; | |
} | |
else testNode = null; | |
} | |
if (testNode && this._getFilteredStatus(testNode) === this.NodeFilter.FILTER_ACCEPT) { | |
break; | |
} | |
} | |
(testNode) && (this.currentNode = testNode); | |
return testNode; | |
}; | |
TreeWalker.prototype.nextSibling = function () { | |
var testNode = this.currentNode; | |
while(testNode) { | |
(testNode.nextSibling) && (testNode = testNode.nextSibling); | |
if(this._getFilteredStatus(testNode) === this.NodeFilter.FILTER_ACCEPT) { | |
break; | |
} | |
} | |
(testNode) && (this.currentNode = testNode); | |
return testNode; | |
}; | |
TreeWalker.prototype.previousSibling = function () { | |
var testNode = this.currentNode; | |
while(testNode) { | |
(testNode.previousSibling) && (testNode = testNode.previousSibling); | |
if(this._getFilteredStatus(testNode) == this.NodeFilter.FILTER_ACCEPT) { | |
break; | |
} | |
} | |
(testNode) && (this.currentNode = testNode); | |
return testNode; | |
}; | |
TreeWalker.prototype._getFilteredStatus = function (node) { | |
var mask = ({ | |
/* ELEMENT_NODE */ 1: this.NodeFilter.SHOW_ELEMENT, | |
/* ATTRIBUTE_NODE */ 2: this.NodeFilter.SHOW_ATTRIBUTE, | |
/* TEXT_NODE */ 3: this.NodeFilter.SHOW_TEXT, | |
/* CDATA_SECTION_NODE */ 4: this.NodeFilter.SHOW_CDATA_SECTION, | |
/* ENTITY_REFERENCE_NODE */ 5: this.NodeFilter.SHOW_ENTITY_REFERENCE, | |
/* ENTITY_NODE */ 6: this.NodeFilter.SHOW_PROCESSING_INSTRUCTION, | |
/* PROCESSING_INSTRUCTION_NODE */ 7: this.NodeFilter.SHOW_PROCESSING_INSTRUCTION, | |
/* COMMENT_NODE */ 8: this.NodeFilter.SHOW_COMMENT, | |
/* DOCUMENT_NODE */ 9: this.NodeFilter.SHOW_DOCUMENT, | |
/* DOCUMENT_TYPE_NODE */ 10: this.NodeFilter.SHOW_DOCUMENT_TYPE, | |
/* DOCUMENT_FRAGMENT_NODE */ 11: this.NodeFilter.SHOW_DOCUMENT_FRAGMENT, | |
/* NOTATION_NODE */ 12: this.NodeFilter.SHOW_NOTATION | |
})[node.nodeType]; | |
return ( | |
(mask && (this.whatToShow & mask) == 0) ? | |
this.NodeFilter.FILTER_REJECT : | |
(this.filter && this.filter.acceptNode) ? | |
this.filter.acceptNode(node) : | |
this.NodeFilter.FILTER_ACCEPT | |
); | |
}; | |
if (!document.createTreeWalker) { | |
document.createTreeWalker = function (root, whatToShow, filter, expandEntityReferences) { | |
return new TreeWalker(root, whatToShow, filter, expandEntityReferences); | |
}; | |
} |
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