chore(ui-toolkit): add pseudo random instead Math.random (#2997)

apps/trading/components/app-loader/app-loader.tsx

@@ -12,7 +12,7 @@ import type { ReactNode } from 'react';
 import { AppFailure } from './app-failure';
 import { Web3Provider } from './web3-provider';
 
-const DynamicLoader = dynamic(() => import('../preloader/preloader'), {
+export const DynamicLoader = dynamic(() => import('../preloader/preloader'), {
   loading: () => <>Loading...</>,
 });
 

apps/trading/pages/_app.page.tsx

@@ -33,7 +33,7 @@ import { Connectors } from '../lib/vega-connectors';
 import { ViewingBanner } from '../components/viewing-banner';
 import { Banner } from '../components/banner';
 import classNames from 'classnames';
-import { AppLoader } from '../components/app-loader';
+import { AppLoader, DynamicLoader } from '../components/app-loader';
 
 const DEFAULT_TITLE = t('Welcome to Vega trading!');
 
@@ -115,7 +115,7 @@ function VegaTradingApp(props: AppProps) {
   // Prevent HashRouter from being server side rendered as it
   // relies on presence of document object
   if (status === 'default') {
-    return null;
+    return <DynamicLoader />;
   }
 
   return (

apps/trading/pages/_document.page.tsx

@@ -12,6 +12,8 @@ export default function Document() {
           type="font/woff2"
           crossOrigin="anonymous"
         />
+        {/* eslint-disable-next-line @next/next/no-css-tags */}
+        <link rel="stylesheet" href="/preloader.css" media="all" />
         <link
           rel="icon"
           type="image/x-icon"

apps/trading/public/preloader.css

@@ -0,0 +1,106 @@
+.pre-loader {
+  display: flex;
+  width: 100%;
+  min-height: 100vh;
+  justify-content: center;
+  align-items: center;
+}
+.pre-loader .loader-item:nth-child(0) {
+  animation-delay: 0ms;
+  animation-direction: reverse;
+}
+.pre-loader .loader-item:first-child {
+  animation-delay: -0.2s;
+  animation-direction: alternate;
+}
+.pre-loader .loader-item:nth-child(2) {
+  animation-delay: 0.1s;
+  animation-direction: reverse;
+}
+.pre-loader .loader-item:nth-child(3) {
+  animation-delay: -0.15s;
+  animation-direction: alternate;
+}
+.pre-loader .loader-item:nth-child(4) {
+  animation-delay: 1s;
+  animation-direction: reverse;
+}
+.pre-loader .loader-item:nth-child(5) {
+  animation-delay: -0.25s;
+  animation-direction: alternate;
+}
+.pre-loader .loader-item:nth-child(6) {
+  animation-delay: 0.3s;
+  animation-direction: reverse;
+}
+.pre-loader .loader-item:nth-child(7) {
+  animation-delay: -1.05s;
+  animation-direction: alternate;
+}
+.pre-loader .loader-item:nth-child(8) {
+  animation-delay: 0.8s;
+  animation-direction: reverse;
+}
+.pre-loader .loader-item:nth-child(9) {
+  animation-delay: -0.9s;
+  animation-direction: alternate;
+}
+.pre-loader .loader-item:nth-child(10) {
+  animation-delay: 0.5s;
+  animation-direction: reverse;
+}
+.pre-loader .loader-item:nth-child(11) {
+  animation-delay: -2.75s;
+  animation-direction: alternate;
+}
+.pre-loader .loader-item:nth-child(12) {
+  animation-delay: 2.4s;
+  animation-direction: reverse;
+}
+.pre-loader .loader-item:nth-child(13) {
+  animation-delay: -0.65s;
+  animation-direction: alternate;
+}
+.pre-loader .loader-item:nth-child(14) {
+  animation-delay: 0.7s;
+  animation-direction: reverse;
+}
+.pre-loader .loader-item:nth-child(15) {
+  animation-delay: -3s;
+  animation-direction: alternate;
+}
+.pre-loader .loader-item:nth-child(16) {
+  animation-delay: 2.4s;
+  animation-direction: reverse;
+}
+.pre-loader .pre-loader-center {
+  align-items: center;
+  display: flex;
+  flex-direction: column;
+}
+.pre-loader .pre-loader-wrapper {
+  width: 50px;
+  height: 50px;
+  display: flex;
+  flex-wrap: wrap;
+}
+.pre-loader .loader-item {
+  width: 10px;
+  height: 10px;
+  background: #000;
+  animation: flickering 0.4s steps(2, jump-none) infinite alternate;
+}
+@keyframes flickering {
+  0% {
+    opacity: 1;
+  }
+  25% {
+    opacity: 1;
+  }
+  26% {
+    opacity: 0;
+  }
+  to {
+    opacity: 0;
+  }
+}

libs/ui-toolkit/src/components/loader/loader.tsx

@@ -1,5 +1,13 @@
 import classNames from 'classnames';
-import { useEffect, useState } from 'react';
+import { useEffect, useMemo, useState } from 'react';
+
+const pseudoRandom = (seed: number) => {
+  let value = seed;
+  return () => {
+    value = (value * 16807) % 2147483647;
+    return value / 1000000000;
+  };
+};
 
 export interface LoaderProps {
   size?: 'small' | 'large';
@@ -35,6 +43,8 @@ export const Loader = ({
     size === 'small' ? 'w-[15px] h-[15px]' : 'w-[50px] h-[50px]';
   const items = size === 'small' ? 9 : 16;
 
+  const generate = useMemo(() => pseudoRandom(1), []);
+
   return (
     <div
       className="flex flex-col items-center pre-loader-center"
@@ -47,7 +57,7 @@ export const Loader = ({
               className={itemClasses}
               key={i}
               style={{
-                opacity: Math.random() > 0.75 ? 1 : 0,
+                opacity: generate() > 1.5 ? 1 : 0,
               }}
             />
           );