Duolingo Trim tree [mirror]

Duolingo_Trim_tree.user.js

// ==UserScript==
// @name         Duolingo Trim tree
// @namespace    9a84a9d7b3fef7de9d2fd7155dcd794c
// @description  Hides all golden skills with a button.
// @author       Arek Olek
// @match        https://www.duolingo.com/*
// @icon         https://raw.githubusercontent.com/camiloaa/duolingotreeenhancer/master/duolingo.png
// @grant        none
// @updateURL    https://gist.github.com/camiloaa/6b902c11f7ab44a4c3ef/raw/Duolingo_Trim_tree.user.js
// @downloadURL  https://gist.github.com/camiloaa/6b902c11f7ab44a4c3ef/raw/Duolingo_Trim_tree.user.js
// @version      1.8.5
// ==/UserScript==

// Credit for [the idea](https://www.duolingo.com/comment/7146895) goes to Thomas de Roo.

var DuoState = JSON.parse(localStorage.getItem('duo.state'));
var threshold_class = ["XXX0", "_22Kj3", "XXX2", "rgwrb", "_2SEng", "dYBTa"];

var observer = new MutationObserver(function(mutations){
    initialize();
});

function initialize() {
    // Without the timeout, only some of the skills get hidden
    setTimeout(function() {
    	if (!document.getElementById("toggleskills"))
    	{
            var tree = document.getElementsByClassName("mAsUf")[0];
            var flag = tree.getElementsByClassName("_2XSZu")[0];
            var button = document.createElement("button");
            button.id = "toggleskills";
            button.onclick = updateOnClick;
            button.className = "_3LN9C _3QG2_ _1vaUe _3IS_q _1XnsG _1vaUe _3IS_q";
            button.style = "margin-left: 5px; width: 130px; height: 42px; "
            	+ "display: block;"
            	+ "visibility: visible;";
            tree.insertBefore(button, flag);
            update();
    	}

        // Handle switching languages
    }, 100);
}

function updateOnClick() {
    var item_name = "trim_treshold-" + DuoState.user.fromLanguage + "-"
                                     + DuoState.user.learningLanguage;
    var threshold = localStorage.getItem(item_name, 6);
    if (threshold == null) threshold = 6;
    localStorage.setItem(item_name, strongerThan(threshold > 5 ? 0 : threshold));
    update();
}

function update() {
    clearTimeout(update.tid);
    var item_name = "trim_treshold-" + DuoState.user.fromLanguage + "-"
                                     + DuoState.user.learningLanguage;
    var threshold = localStorage.getItem(item_name, 6);
    if (threshold == null) threshold = 6;
    var trimmed = threshold < 6;

    // Show current level and next available action
    var button = document.getElementById("toggleskills");
    button.textContent = trimmed ? threshold-1 + ' bars or less' : 'Everything';
    update.tid = setTimeout(function() {
    	button.textContent = trimmed ? 'Grow tree' : 'Trim tree';
    	}, 2000);

    // Show or hide items depending on current state
    for(var strength = 0; strength <= 5; ++strength)
    {
    	var tree = document.getElementsByClassName("i12-l")[0];
    	nodes = tree.getElementsByClassName(threshold_class[strength]);
    	var new_display = (strength >= threshold) ? "none" : "";
    	for (var i = 0; i < nodes.length; i++)
    		nodes[i].parentNode.parentNode.style.display = new_display;
    }
    
	var new_display = (trimmed) ? "none" : "";
	nodes = document.getElementsByClassName("_2Np2b");
	for (var i = 0; i < nodes.length; i++)
		nodes[i].parentNode.style.display = new_display;
}

function strongerThan(strength) {
    for(++strength; strength <= 5; ++strength) {
    	var skills = document.getElementsByClassName(threshold_class[strength]);
    	if (skills.length > 0) {
    		break;
    	}
    }
    return strength;
}

// Handle navigation that does not reload the page
new MutationObserver(function() {
	if (window.location.pathname == "/")
		initialize();
}).observe(document.body, {childList: true, subtree: true});