nuxt/dist/pages/runtime/router.options.js

Nuxt is a free and open-source framework with an intuitive and extendable way to create type-safe, performant and production-grade full-stack web applications and websites with Vue.js.

import { START_LOCATION } from "vue-router";
import { useNuxtApp } from "#app/nuxt";
import { isChangingPage } from "#app/components/utils";
import { useRouter } from "#app/composables/router";
export default {
  scrollBehavior(to, from, savedPosition) {
    const nuxtApp = useNuxtApp();
    const hashScrollBehaviour = useRouter().options?.scrollBehaviorType ?? "auto";
    if (to.path === from.path) {
      if (from.hash && !to.hash) {
        return { left: 0, top: 0 };
      }
      if (to.hash) {
        return { el: to.hash, top: _getHashElementScrollMarginTop(to.hash), behavior: hashScrollBehaviour };
      }
      return false;
    }
    const routeAllowsScrollToTop = typeof to.meta.scrollToTop === "function" ? to.meta.scrollToTop(to, from) : to.meta.scrollToTop;
    if (routeAllowsScrollToTop === false) {
      return false;
    }
    const hookToWait = nuxtApp._runningTransition ? "page:transition:finish" : "page:loading:end";
    return new Promise((resolve) => {
      if (from === START_LOCATION) {
        resolve(_calculatePosition(to, from, savedPosition, hashScrollBehaviour));
        return;
      }
      nuxtApp.hooks.hookOnce(hookToWait, () => {
        requestAnimationFrame(() => resolve(_calculatePosition(to, from, savedPosition, hashScrollBehaviour)));
      });
    });
  }
};
function _getHashElementScrollMarginTop(selector) {
  try {
    const elem = document.querySelector(selector);
    if (elem) {
      return (Number.parseFloat(getComputedStyle(elem).scrollMarginTop) || 0) + (Number.parseFloat(getComputedStyle(document.documentElement).scrollPaddingTop) || 0);
    }
  } catch {
  }
  return 0;
}
function _calculatePosition(to, from, savedPosition, defaultHashScrollBehaviour) {
  if (savedPosition) {
    return savedPosition;
  }
  const isPageNavigation = isChangingPage(to, from);
  if (to.hash) {
    return {
      el: to.hash,
      top: _getHashElementScrollMarginTop(to.hash),
      behavior: isPageNavigation ? defaultHashScrollBehaviour : "instant"
    };
  }
  return {
    left: 0,
    top: 0
  };
}