70 lines
1.9 KiB
JavaScript
70 lines
1.9 KiB
JavaScript
'use strict';
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const TREE = Symbol();
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const ROOT = Symbol();
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const NEXT = Symbol();
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const ITERATE_FUNC = Symbol();
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class TreeIterator {
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constructor(tree, root, firstResult, iterateFunction) {
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this[TREE] = tree;
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this[ROOT] = root;
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this[NEXT] = firstResult;
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this[ITERATE_FUNC] = iterateFunction;
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}
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next() {
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const tree = this[TREE];
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const iterateFunc = this[ITERATE_FUNC];
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const root = this[ROOT];
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if (!this[NEXT]) {
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return {
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done: true,
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value: root,
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};
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}
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const value = this[NEXT];
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if (iterateFunc === 1) {
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this[NEXT] = tree._node(value).previousSibling;
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}
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else if (iterateFunc === 2) {
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this[NEXT] = tree._node(value).nextSibling;
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}
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else if (iterateFunc === 3) {
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this[NEXT] = tree._node(value).parent;
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}
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else if (iterateFunc === 4) {
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this[NEXT] = tree.preceding(value, {root: root});
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}
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else /* if (iterateFunc === 5)*/ {
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this[NEXT] = tree.following(value, {root: root});
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}
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return {
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done: false,
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value: value,
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};
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}
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}
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Object.defineProperty(TreeIterator.prototype, Symbol.iterator, {
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value: function() {
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return this;
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},
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writable: false,
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});
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TreeIterator.PREV = 1;
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TreeIterator.NEXT = 2;
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TreeIterator.PARENT = 3;
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TreeIterator.PRECEDING = 4;
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TreeIterator.FOLLOWING = 5;
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Object.freeze(TreeIterator);
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Object.freeze(TreeIterator.prototype);
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module.exports = TreeIterator;
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