devdocs/assets/javascripts/lib/page.js

/*
 * Based on github.com/visionmedia/page.js
 * Licensed under the MIT license
 * Copyright 2012 TJ Holowaychuk <tj@vision-media.ca>
 */

let running = false;
let currentState = null;
const callbacks = [];

this.page = function (value, fn) {
  if (typeof value === "function") {
    page("*", value);
  } else if (typeof fn === "function") {
    const route = new Route(value);
    callbacks.push(route.middleware(fn));
  } else if (typeof value === "string") {
    page.show(value, fn);
  } else {
    page.start(value);
  }
};

page.start = function (options) {
  if (options == null) {
    options = {};
  }
  if (!running) {
    running = true;
    addEventListener("popstate", onpopstate);
    addEventListener("click", onclick);
    page.replace(currentPath(), null, null, true);
  }
};

page.stop = function () {
  if (running) {
    running = false;
    removeEventListener("click", onclick);
    removeEventListener("popstate", onpopstate);
  }
};

page.show = function (path, state) {
  let res;
  if (path === currentState?.path) {
    return;
  }
  const context = new Context(path, state);
  const previousState = currentState;
  currentState = context.state;
  if ((res = page.dispatch(context))) {
    currentState = previousState;
    location.assign(res);
  } else {
    context.pushState();
    updateCanonicalLink();
    track();
  }
  return context;
};

page.replace = function (path, state, skipDispatch, init) {
  let result;
  let context = new Context(path, state || currentState);
  context.init = init;
  currentState = context.state;
  if (!skipDispatch) {
    result = page.dispatch(context);
  }
  if (result) {
    context = new Context(result);
    context.init = init;
    currentState = context.state;
    page.dispatch(context);
  }
  context.replaceState();
  updateCanonicalLink();
  if (!skipDispatch) {
    track();
  }
  return context;
};

page.dispatch = function (context) {
  let i = 0;
  var next = function () {
    let fn, res;
    if ((fn = callbacks[i++])) {
      res = fn(context, next);
    }
    return res;
  };
  return next();
};

page.canGoBack = () => !Context.isIntialState(currentState);

page.canGoForward = () => !Context.isLastState(currentState);

const currentPath = () => location.pathname + location.search + location.hash;

class Context {
  static isIntialState(state) {
    return state.id === 0;
  }

  static isLastState(state) {
    return state.id === this.stateId - 1;
  }

  static isInitialPopState(state) {
    return state.path === this.initialPath && this.stateId === 1;
  }

  static isSameSession(state) {
    return state.sessionId === this.sessionId;
  }

  constructor(path, state) {
    this.initialPath = currentPath();
    this.sessionId = Date.now();
    this.stateId = 0;
    if (path == null) {
      path = "/";
    }
    this.path = path;
    if (state == null) {
      state = {};
    }
    this.state = state;
    this.pathname = this.path.replace(
      /(?:\?([^#]*))?(?:#(.*))?$/,
      (_, query, hash) => {
        this.query = query;
        this.hash = hash;
        return "";
      },
    );

    if (this.state.id == null) {
      this.state.id = this.constructor.stateId++;
    }
    if (this.state.sessionId == null) {
      this.state.sessionId = this.constructor.sessionId;
    }
    this.state.path = this.path;
  }

  pushState() {
    history.pushState(this.state, "", this.path);
  }

  replaceState() {
    try {
      history.replaceState(this.state, "", this.path);
    } catch (error) {} // NS_ERROR_FAILURE in Firefox
  }
}

class Route {
  constructor(path, options) {
    this.path = path;
    if (options == null) {
      options = {};
    }
    this.keys = [];
    this.regexp = pathToRegexp(this.path, this.keys);
  }

  middleware(fn) {
    return (context, next) => {
      let params;
      if (this.match(context.pathname, (params = []))) {
        context.params = params;
        return fn(context, next);
      } else {
        return next();
      }
    };
  }

  match(path, params) {
    let matchData;
    if (!(matchData = this.regexp.exec(path))) {
      return;
    }

    const iterable = matchData.slice(1);
    for (let i = 0; i < iterable.length; i++) {
      var key;
      var value = iterable[i];
      if (typeof value === "string") {
        value = decodeURIComponent(value);
      }
      if ((key = this.keys[i])) {
        params[key.name] = value;
      } else {
        params.push(value);
      }
    }
    return true;
  }
}

var pathToRegexp = function (path, keys) {
  if (path instanceof RegExp) {
    return path;
  }

  if (path instanceof Array) {
    path = `(${path.join("|")})`;
  }
  path = path
    .replace(/\/\(/g, "(?:/")
    .replace(
      /(\/)?(\.)?:(\w+)(?:(\(.*?\)))?(\?)?/g,
      (_, slash, format, key, capture, optional) => {
        if (slash == null) {
          slash = "";
        }
        if (format == null) {
          format = "";
        }
        keys.push({ name: key, optional: !!optional });
        let str = optional ? "" : slash;
        str += "(?:";
        if (optional) {
          str += slash;
        }
        str += format;
        str += capture || (format ? "([^/.]+?)" : "([^/]+?)");
        str += ")";
        if (optional) {
          str += optional;
        }
        return str;
      },
    )
    .replace(/([\/.])/g, "\\$1")
    .replace(/\*/g, "(.*)");

  return new RegExp(`^${path}$`);
};

var onpopstate = function (event) {
  if (!event.state || Context.isInitialPopState(event.state)) {
    return;
  }

  if (Context.isSameSession(event.state)) {
    page.replace(event.state.path, event.state);
  } else {
    location.reload();
  }
};

var onclick = function (event) {
  try {
    if (
      event.which !== 1 ||
      event.metaKey ||
      event.ctrlKey ||
      event.shiftKey ||
      event.defaultPrevented
    ) {
      return;
    }
  } catch (error) {
    return;
  }

  let link = $.eventTarget(event);
  while (link && link.tagName !== "A") {
    link = link.parentNode;
  }

  if (link && !link.target && isSameOrigin(link.href)) {
    event.preventDefault();
    let path = link.pathname + link.search + link.hash;
    path = path.replace(/^\/\/+/, "/"); // IE11 bug
    page.show(path);
  }
};

var isSameOrigin = (url) =>
  url.startsWith(`${location.protocol}//${location.hostname}`);

var updateCanonicalLink = function () {
  if (!this.canonicalLink) {
    this.canonicalLink = document.head.querySelector('link[rel="canonical"]');
  }
  return this.canonicalLink.setAttribute(
    "href",
    `https://${location.host}${location.pathname}`,
  );
};

const trackers = [];

page.track = function (fn) {
  trackers.push(fn);
};

var track = function () {
  if (app.config.env !== "production") {
    return;
  }
  if (navigator.doNotTrack === "1") {
    return;
  }
  if (navigator.globalPrivacyControl) {
    return;
  }

  const consentGiven = Cookies.get("analyticsConsent");
  const consentAsked = Cookies.get("analyticsConsentAsked");

  if (consentGiven === "1") {
    for (var tracker of trackers) {
      tracker.call();
    }
  } else if (consentGiven === undefined && consentAsked === undefined) {
    // Only ask for consent once per browser session
    Cookies.set("analyticsConsentAsked", "1");

    new app.views.Notif("AnalyticsConsent", { autoHide: null });
  }
};

this.resetAnalytics = function () {
  for (var cookie of document.cookie.split(/;\s?/)) {
    var name = cookie.split("=")[0];
    if (name[0] === "_" && name[1] !== "_") {
      Cookies.expire(name);
    }
  }
};