moth/theme/common.mjs

/**
 * Common functionality
 */
const Millisecond = 1
const Second = Millisecond * 1000
const Minute = Second * 60

/** URL to the top of this MOTH server */
const BaseURL = new URL(".", location)

/** A channel to monitor for state updates (or to notify of state updates) */
const StateUpdateChannel = new BroadcastChannel("StateUpdate")

/**
 * Display a transient message to the user.
 * 
 * @param {String} message Message to display
 * @param {Number} timeout How long before removing this message
 */
function Toast(message, timeout=5*Second) {
    console.info(message)
    for (let toasts of document.querySelectorAll(".toasts")) {
        let p = toasts.appendChild(document.createElement("p"))
        p.classList.add("toast")
        p.textContent = message
        setTimeout(() => p.remove(), timeout)
    }
}

/**
 * Run a function when the DOM has been loaded.
 * 
 * @param {function():void} cb Callback function
 */
function WhenDOMLoaded(cb) {
    if (document.readyState === "loading") {
        document.addEventListener("DOMContentLoaded", cb)
    } else {
        cb()
    }    
}

/**
 * Interprets a String as a Boolean.
 * 
 * Values like "no" or "disabled" to mean false here.
 * 
 * @param {String} s 
 * @returns {Boolean}
 */
function StringTruthy(s) {
    switch (s.toLowerCase()) {
        case "disabled":
        case "no":
        case "off":
        case "false":
            return false
    }
    return true
}


/**
 * Fetch the configuration object for this theme.
 * 
 * @returns {Promise.<Object>}
 */
async function Config() {
    let obj = {}
    try {
        let resp = await fetch(
            new URL("config.json", BaseURL), 
            {
                cache: "no-cache"
            },
        )
        obj = await resp.json()
    }
    catch(err) {
        obj = {}
    }
    return obj
}

export {
    Millisecond,
    Second,
    Minute,
    StateUpdateChannel,
    BaseURL,
    Toast,
    WhenDOMLoaded,
    StringTruthy,
    Config,
}