vndb/mithril-vndb
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This commit is contained in:
Leo Horie 2014-08-10 22:48:37 -04:00
parent b28dedaa73
commit 5bbd6c6478
1 changed files with 28 additions and 2 deletions
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30
mithril.js
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@ -29,6 +29,21 @@ Mithril = m = new function app(window, undefined) {
return cell
}
function build(parentElement, parentTag, parentCache, parentIndex, data, cached, shouldReattach, index, editable, namespace, configs) {
//`build` is a recursive function that manages creation/diffing/removal of DOM elements based on comparison between `data` and `cached`
//`parentElement` is a DOM element used for W3C DOM API calls
//`parentTag` is only used for handling a corner case for textarea values
//`parentCache` is used to remove nodes in some multi-node cases
//`parentIndex` and `index` are used to figure out the offset of nodes. They're artifacts from before arrays started being flattened and are likely refactorable
//`data` and `cached` are, respectively, the new and old nodes being diffed
//`shouldReattach` is a flag indicating whether a parent node was recreated (if so, and if this node is reused, then this node must reattach itself to the new parent)
//`editable` is a flag that indicates whether an ancestor is contenteditable
//`namespace` indicates the closest HTML namespace as it cascades down from an ancestor
//`configs` is a list of config functions to run after the topmost `build` call finishes running
//there's logic that relies on the assumption that null and undefined data are equivalent to empty strings
//- this prevents lifecycle surprises from procedural helpers that mix implicit and explicit return statements
//- it simplifies diffing code
if (data === undefined || data === null) data = ""
if (data.subtree === "retain") return cached
@ -50,6 +65,12 @@ Mithril = m = new function app(window, undefined) {
data = flatten(data)
var nodes = [], intact = cached.length === data.length, subArrayCount = 0
//key algorithm: sort elements without recreating them if keys are present
//1) create a map of all existing keys, and mark all for deletion
//2) add new keys to map and mark them for addition
//3) if key exists in new list, change action from deletion to a move
//4) for each key, handle its corresponding action as marked in previous steps
//5) copy unkeyed items into their respective gaps
var DELETION = 1, INSERTION = 2 , MOVE = 3
var existing = {}, unkeyed = [], shouldMaintainIdentities = false
for (var i = 0; i < cached.length; i++) {
@ -101,6 +122,7 @@ Mithril = m = new function app(window, undefined) {
cached.nodes = []
for (var i = 0, child; child = parentElement.childNodes[i]; i++) cached.nodes.push(child)
}
//end key algorithm
for (var i = 0, cacheCount = 0; i < data.length; i++) {
var item = build(parentElement, parentTag, cached, index, data[i], cached[cacheCount], shouldReattach, index + subArrayCount || subArrayCount, editable, namespace, configs)
@ -125,7 +147,8 @@ Mithril = m = new function app(window, undefined) {
}
}
else if (dataType == "[object Object]") {
else if (data !== undefined && dataType == "[object Object]") {
//if an element is different enough from the one in cache, recreate it
if (data.tag != cached.tag || Object.keys(data.attrs).join() != Object.keys(cached.attrs).join() || data.attrs.id != cached.attrs.id) {
clear(cached.nodes)
if (cached.configContext && typeof cached.configContext.onunload == "function") cached.configContext.onunload()
@ -153,11 +176,13 @@ Mithril = m = new function app(window, undefined) {
cached.nodes.intact = true
if (shouldReattach === true) parentElement.insertBefore(node, parentElement.childNodes[index] || null)
}
//schedule configs to be called. They are called after `build` finishes running
if (typeof data.attrs["config"] === "function") {
configs.push(data.attrs["config"].bind(window, node, !isNew, cached.configContext = cached.configContext || {}, cached))
}
}
else {
else if (typeof dataType != "function") {
//handle text nodes
var nodes
if (cached.nodes.length === 0) {
if (data.$trusted) {
@ -178,6 +203,7 @@ Mithril = m = new function app(window, undefined) {
nodes = injectHTML(parentElement, index, data)
}
else {
//corner case: replacing the nodeValue of a text node that is a child of a textarea/contenteditable doesn't work
if (parentTag === "textarea") parentElement.value = data
else if (editable) editable.innerHTML = data
else {