duolingo-fade-strength.js

customjsReady("div[data-test='skill-tree']", () => {
    const userName = $("div#root div[data-test='user-dropdown'] > span:first").text();
    $.get(`/users/${userName}`, (d) => {
        const language = Object.keys(d.language_data)[0];
        const skills = d.language_data[language].skills;
        const $skills = $("div[data-test='skill-tree'] > div > a");
        $skills.each((i, d) => {
            const $skill = $(d);
            const skillName = $skill.find("> div > span").text()
            if (skillName && skillName.length) {
                const skill = skills.find((skill) => skill.short == skillName);
                if (skill && skill.strength < 1 && skill.learned) {
                    const opacity = 0.5 * skill.strength;
                    const $skillIcon = $skill.find("> div:first > div:first")
                    $skillIcon.css("opacity", opacity)
                }
            }
        })
    });
});