getCookies.js

// Return the document's cookies as a Map object.
// Assume that cookie values are encoded with encodeURIComponent().
function getCookies() {
    let cookies = new Map();    // The object we will return
    let all = document.cookie;  // Get all cookies in one big string
    let list = all.split("; "); // Split into individual name/value pairs
    for(let cookie of list) {   // For each cookie in that list
        if (!cookie.includes("=")) continue; // Skip if there is no = sign
        let p = cookie.indexOf("=");         // Find the first = sign
        let name = cookie.substring(0, p);   // Get cookie name
        let value = cookie.substring(p+1);   // Get cookie value
        value = decodeURIComponent(value);   // Decode the value
        cookies.set(name, value);            // Remember cookie name and value
    }
    return cookies;
}