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Copy pathdiff.js
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62 lines (57 loc) · 2.21 KB
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var patch = require('./patch');
// diff函数，对比两棵树
function diff(oldTree, newTree) {
var index = 0; // 当前节点的标志
var patches = {}; // 用来记录每个节点差异的对象
dfsWalk(oldTree, newTree, index, patches);
return patches;
}
// 对两棵树进行深度优先遍历
function dfsWalk(oldNode, newNode, index, patches) {
// 对比oldNode和newNode的不同，记录下来
var currentPatch = [];
// 如果node是被移除的
if(newNode === null) {
// 真实的DOM节点在节点重新排序的时候被移除，所以这里不需要进行处理
} else if((typeof oldNode === 'string') && (typeof newNode === 'string')) {
// 更换节点的文本
if(newNode !== oldNode) {
currentPatch.push({type: patch.TEXT, content: newNode})
}
} else if(oldNode.tagName === newNode.tagName && oldNode.key === newNode.key) {
// 如果新节点跟旧节点相同，则比较节点的属性和子节点
// 比较属性
var propsPatches = diffProps(oldNode, newNode);
if(propsPatches) {
currentPatch.push({ type: patch.PROPS, props: propsPatches });
}
// 比较子节点,如果子节点有ignore这个属性，则不对这个子节点进行比较
if(!isIgnoreChildren(newNode)) {
diffChildren(
oldNode.children,
newNode.children,
index,
patches,
currentPatch
);
}
} else {
// 如果新节点和旧节点的tag不一样，则直接替换节点
currentPatch.push({ type: patch.REPLACE, node: newNode })
}
if(currentPatch.length) {
patches[index] = currentPatch;
}
}
// 遍历子节点
function diffChildren(oldChildren, newChildren, index, patches, currentPatch) {
var leftNode = null;
var currentNodeIndex = index;
oldChildren.forEach(function (child, i) {
var newChild = newChildren[i];
currentNodeIndex = (leftNode && leftNode.count)
? currentNodeIndex + leftNode.count + 1
: currentNodeIndex + 1
dfsWalk(child, newChild, currentNodeIndex, patches) // 深度遍历子节点
})
}