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Wait For Selector

Waits for selectors to match newly added nodes

当前为 2021-09-14 提交的版本，查看 最新版本。

此脚本不应直接安装。它是供其他脚本使用的外部库，要使用该库请加入元指令 // @require https://update.cn-greasyfork.org/scripts/432418/970668/Wait%20For%20Selector.js 

// ==UserScript==
// @name         Wait For Selector
// @version      0.1.0
// @description  Waits for selectors to match newly added nodes
// @author       Kumirei
// @include      *community.wanikani.com*
// @grant        none
// ==/UserScript==

(function($) {
    // Create new observer on body to monitor all DOM changes
    let observer = new MutationObserver(mutationHandler)
    observer.observe(document.getElementsByTagName('body')[0], {childList: true, subtree: true})

    // Interface for interacting with the library
    let interface = {
        version: GM_info.script.version,
        observer: observer,
        wait: waitForSelector,
        unwait: unwaitID,
        waits: {},
        waitsByID: {},
        nextID: 0
    }

    // Start
    installInterface()

    // Creates a new entry to search for whenever a new element is added to the DOM
    function waitForSelector(preSelector, selector, callback) {
        if (selector.match(`${preSelector}$`) === null) throw ('preSelector must match the end of the selector')
        if (!interface.waits[selector]) interface.waits[selector] = {}
        interface.waits[selector][interface.nextID] = callback
        interface.waits[selector].pre = preSelector
        interface.waitsByID[interface.nextID] = selector
        return interface.nextID++
    }

    // Deletes a previously registered selector
    function unwaitID(ID) {
        delete interface.waits[interface.waitsByID[ID]][ID]
    }

    // Makes sure that the public interface is the newest version and the same as the local one
    function installInterface() {
        let wfke = window.wkfe
        if (!wfke) window.wfke = interface
        else if (wfke.version < interface.version) {
            wfke.version = interface.version
            wfke.observer.disconnect()
            wfke.observer = interface.observer
            wfke.wait = interface.wait
            wfke.unwait = interface.unwait
        }
        interface = wfke || interface
    }

    // Searches the added nodes and matches them with the provided selectors. Calls the callback for every match.
    function mutationHandler(mutations) {
        for (let mutation of mutations) {
            let added = mutation.addedNodes
            for (let node of added) {
                if (node.nodeType === 1) {
                    let sibling = node.previousElementSibling
                    let target = sibling ? sibling : node.parentElement
                    for (let selector in interface.waits) {
                        let query = (sibling?'+ ':'> ')+interface.waits[selector].pre
                        $(target).find(query).each((i, e)=>{
                            $(selector).each((I, E)=>{
                                if (e.isSameNode(E)) {
                                    for (let callback of Object.values(interface.waits[selector])) {
                                        if (typeof callback === "function") callback(E)
                                    }
                                }
                            })
                        })
                    }
                }
            }
        }
    }
})(window.jQuery);