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Squire/source/TreeWalker.js
Neil Jenkins 597024eecb Remove FILTER_(ACCEPT|SKIP) constants.
Just return a boolean for the TreeWalker filter fn. This diverges from the spec,
but since the goal of this implementation is not to fully implement the spec
and we're never going to use a native implementation, this doesn't matter and
the code is easier to read when the function is just returning a boolean like
any normal filter function.
2014-09-04 17:24:31 +07:00

90 lines
2.3 KiB
JavaScript

/*jshint strict:false */
/*
Native TreeWalker is buggy in IE and Opera:
* IE9/10 sometimes throw errors when calling TreeWalker#nextNode or
TreeWalker#previousNode. No way to feature detect this.
* Some versions of Opera have a bug in TreeWalker#previousNode which makes
it skip to the wrong node.
Rather than risk further bugs, it's easiest just to implement our own
(subset) of the spec in all browsers.
*/
var typeToBitArray = {
// ELEMENT_NODE
1: 1,
// ATTRIBUTE_NODE
2: 2,
// TEXT_NODE
3: 4,
// COMMENT_NODE
8: 128,
// DOCUMENT_NODE
9: 256,
// DOCUMENT_FRAGMENT_NODE
11: 1024
};
function TreeWalker ( root, nodeType, filter ) {
this.root = this.currentNode = root;
this.nodeType = nodeType;
this.filter = filter;
}
TreeWalker.prototype.nextNode = function () {
var current = this.currentNode,
root = this.root,
nodeType = this.nodeType,
filter = this.filter,
node;
while ( true ) {
node = current.firstChild;
while ( !node && current ) {
if ( current === root ) {
break;
}
node = current.nextSibling;
if ( !node ) { current = current.parentNode; }
}
if ( !node ) {
return null;
}
if ( ( typeToBitArray[ node.nodeType ] & nodeType ) &&
filter( node ) ) {
this.currentNode = node;
return node;
}
current = node;
}
};
TreeWalker.prototype.previousNode = function () {
var current = this.currentNode,
root = this.root,
nodeType = this.nodeType,
filter = this.filter,
node;
while ( true ) {
if ( current === root ) {
return null;
}
node = current.previousSibling;
if ( node ) {
while ( current = node.lastChild ) {
node = current;
}
} else {
node = current.parentNode;
}
if ( !node ) {
return null;
}
if ( ( typeToBitArray[ node.nodeType ] & nodeType ) &&
filter( node ) ) {
this.currentNode = node;
return node;
}
current = node;
}
};