From 124bdd64345bc64eb84879929f0e57cbb8752e34 Mon Sep 17 00:00:00 2001
From: Wes Bos <wesbos@gmail.com>
Date: Wed, 22 Jan 2020 12:14:25 -0500
Subject: [PATCH] make the scroll to top better

---
 gatsby-node.js               |  1 -
 src/components/BackToTop.js  | 56 ++++++++++++++++++++++++++++++++++++
 src/components/Person.js     | 20 ++++++++++++-
 src/components/layout.js     |  1 +
 src/context/FilterContext.js |  3 +-
 src/data.js                  |  3 --
 src/pages/index.js           | 14 ++-------
 7 files changed, 80 insertions(+), 18 deletions(-)
 create mode 100644 src/components/BackToTop.js

diff --git a/gatsby-node.js b/gatsby-node.js
index f28b49d8..8f64c729 100644
--- a/gatsby-node.js
+++ b/gatsby-node.js
@@ -56,7 +56,6 @@ function sourceNodes({ actions, createNodeId, createContentDigest }) {
   });
 
   // Add Devices to GraphQL API
-  console.log(devices());
   devices().forEach(device => {
     const nodeMeta = {
       id: createNodeId(`device-${device.name}`),
diff --git a/src/components/BackToTop.js b/src/components/BackToTop.js
new file mode 100644
index 00000000..faaab8a1
--- /dev/null
+++ b/src/components/BackToTop.js
@@ -0,0 +1,56 @@
+import React, { useState, useEffect } from 'react';
+import styled from 'styled-components';
+
+const BackToTopLink = styled.a`
+  position: fixed;
+  bottom: 1%;
+  right: 1%;
+  background: var(--pink);
+  color: white;
+  background: rgba(0, 0, 0, 0.5);
+  cursor: pointer;
+  border-radius: 3px;
+  padding: 1rem;
+  transition: opacity 0.2s;
+  opacity: 0;
+  text-decoration: none;
+  ${props =>
+    props.percent > 0.25 &&
+    `
+    opacity: 1;
+  `}
+  @media screen and (max-width: 500px) {
+    display: none;
+  }
+`;
+
+function useScrollPosition() {
+  const [percent, setPercent] = useState(0);
+
+  function handleScroll(event) {
+    console.log(document.documentElement.scrollTop);
+    const howFar =
+      document.documentElement.scrollTop /
+      document.documentElement.scrollTopMax;
+    setPercent(howFar);
+  }
+
+  useEffect(() => {
+    // listen for window scroll event
+    document.addEventListener('scroll', handleScroll);
+    return () => {
+      document.removeEventListener('scroll', handleScroll);
+    };
+  });
+
+  return percent;
+}
+
+export default function BackToTop() {
+  const percent = useScrollPosition();
+  return (
+    <BackToTopLink href="#top" title="Back To Top" percent={percent}>
+      &uarr;
+    </BackToTopLink>
+  );
+}
diff --git a/src/components/Person.js b/src/components/Person.js
index baddbbdb..9c9cef83 100644
--- a/src/components/Person.js
+++ b/src/components/Person.js
@@ -1,13 +1,31 @@
-import React from 'react';
+import React, { useState, useEffect, useRef } from 'react';
 import PropTypes from 'prop-types';
 import { name } from 'country-emoji';
 import styled from 'styled-components';
 import { Tag, Tags } from './Topics';
 import * as icons from '../util/icons';
 
+function useIntersectionObserver(ref) {
+  const [isIntersecting, setIntersecting] = useState(false);
+
+  useEffect(function() {
+    const observer = new IntersectionObserver(function([entry]) {
+      console.log('Run once for every time its on screen');
+      console.log(entry);
+    });
+    // Observe the element we want to observve
+    observer.observe(ref.current);
+
+    return () => {
+      observer.unobserve(ref.current);
+    };
+  });
+}
+
 export default function Person({ person, currentTag }) {
   const url = new URL(person.url);
   const img = `https://images.weserv.nl/?url=https://unavatar.now.sh/${url.host}&w=100&l=9&af&il&n=-1`;
+
   return (
     <PersonWrapper>
       <PersonInner>
diff --git a/src/components/layout.js b/src/components/layout.js
index bef6c484..17e50fdf 100644
--- a/src/components/layout.js
+++ b/src/components/layout.js
@@ -85,6 +85,7 @@ const GlobalStyle = createGlobalStyle`
     font-family: 'Fira Mono', monospace;
     font-weight: 100;
     font-size: 10px;
+    scroll-behavior: smooth;
   }
   body {
     font-size: 2rem;
diff --git a/src/context/FilterContext.js b/src/context/FilterContext.js
index e3f32206..c1d9b98e 100644
--- a/src/context/FilterContext.js
+++ b/src/context/FilterContext.js
@@ -1,5 +1,6 @@
 import React, { createContext, useState } from 'react';
 import { useStaticQuery, graphql } from 'gatsby';
+import PropTypes from 'prop-types';
 
 const FilterContext = createContext();
 
@@ -45,7 +46,7 @@ const FilterProvider = function({ children }) {
 };
 
 FilterProvider.propTypes = {
-  children: React.Children,
+  children: PropTypes.element,
 };
 
 export default FilterContext;
diff --git a/src/data.js b/src/data.js
index 9a1754bb..03752bd2 100644
--- a/src/data.js
+++ b/src/data.js
@@ -2727,7 +2727,6 @@ module.exports = [
       'YouTuber',
       'JavaScript',
       'TypeScript',
-      'Node',
       'React',
       'Node',
       'CSS',
@@ -3699,7 +3698,6 @@ module.exports = [
       'React',
       'TypeScript',
       'JavaScript',
-      'React',
       'Node',
       'CSS',
     ],
@@ -4065,7 +4063,6 @@ module.exports = [
     phone: 'iphone',
     tags: [
       'Architect',
-      'Developer',
       'SitecoreJSS',
       'Sitecore',
       'React',
diff --git a/src/pages/index.js b/src/pages/index.js
index 0519dd91..14a6d27f 100644
--- a/src/pages/index.js
+++ b/src/pages/index.js
@@ -6,17 +6,7 @@ import FilterContext from '../context/FilterContext';
 import Layout from '../components/layout';
 import Person from '../components/Person';
 import Topics from '../components/Topics';
-
-const BackToTopLink = styled.a`
-  position: fixed;
-  bottom: 1%;
-  right: 1%;
-  background: var(--pink);
-  cursor: pointer;
-  border-radius: 3px;
-  padding: 1rem;
-  transition: background-color 0.2s ease 0s;
-`;
+import BackToTop from '../components/BackToTop';
 
 function IndexPage() {
   const { currentTag } = useContext(FilterContext);
@@ -54,7 +44,7 @@ function IndexPage() {
           <Person key={person.name} person={person} currentTag={currentTag} />
         ))}
       </People>
-      <BackToTopLink href="#top">&uarr; Back to top</BackToTopLink>
+      <BackToTop />
     </Layout>
   );
 }