animate div width from left to right-CodePudding

I'm new to animations but I want to animate a skeleton loader. I want it to start from the left at at 0% width, then going to the right, at 100% width, and then have the loader go to zero but in reverse so that it ends on the right with 0% width. My problem is that I cannot get the animation to go out from left to right. I am using react with styled-components. here is my code:

const reveal = keyframes`
  0% {
    width: 0%;
  }
  50% {
    width: 100%;
  }
  100% {
    width: -100%;
  }
`;

const StyledSkeleton = styled.div`
  height: 40px;
  font-size: 64px;
  line-height: 70px;
  overflow: hidden;
  background-color: ${colors.LOADER_BACKGROUND};
  background-size: 100%;

  animation-name: ${reveal};
  animation-duration: 2s;
  animation-timing-function: ease-in;
  animation-delay: 0s;
  animation-iteration-count: infinite;
  animation-direction: normal;
`;

CodePudding user response：

Instead of using width, you could animate the loader's size using absolute position.

.container {
  width: 100%;
  height: 40px;
  position: relative;
}

.loader {
  position: absolute;
  top: 0;
  bottom: 0;
  background-color: red;
  animation-name: animate;
  animation-duration: 2s;
  animation-timing-function: ease-in;
  animation-iteration-count: infinite;
}

@keyframes animate {
   0% {
    left: 0;
    right: 100%;
  }
  50% {
    left: 0;
    right: 0;
  }
  100% {
    left: 100%;
    right: 0;
  }
}

<div class='container'>
  <div class='loader'></div>
</div>

CodePudding user response：

This is how I ended up implementing it. Someone else might have a different use case but the answer from @yeniv enabled me to come to this solution. I am using NextJS with TypeScript and styled components.

import React from 'react';
import styled, { keyframes } from 'styled-components';

import { colors } from '../../../styles';


interface SkeletonProps {
  delay?: number;
  style?: object;
  children?: React.ReactNode;
}

export const Skeleton = ({ delay, children, style = {} }: SkeletonProps): JSX.Element => {

  return (
    <div>
      <Container style={{...style}}>
        <TextContainer>
          {children && children}
        </TextContainer>
        <StyledSkeleton delay={delay} />
      </Container>
    </div>
  );
};


export default Skeleton;





const reveal = keyframes`
  0% {
    display: none;
    opacity: 0;
  }
  50% {
    opacity: 0;
  }
  100% {
    display: inline-block;
    opacity: 1;
  }
`;

const animate = keyframes`
  0% {
   left: 0;
   right: 100%;
 }
 50% {
   left: 0;
   right: 0;
 }
 100% {
   left: 100%;
   right: 0;
 }
`;

const Container = styled.div`
  position: relative;
  height: 40px;
  width: 100%;
`;

interface TextContainerProps {
  delay?: number;
}

const TextContainer = styled.span<TextContainerProps>`
  animation-name: ${reveal};
  animation-duration: 2s;
  animation-delay: ${props => `${props.delay}s`};
  animation-timing-function: ease-in;
  animation-iteration-count: 1;
`;

interface StyledSkeletonProps {
  delay?: number;
}

const StyledSkeleton = styled.div<StyledSkeletonProps>`
  position: absolute;
  top: 0;
  bottom: 0;
  overflow: hidden;

  background-color: ${colors.LOADER_BACKGROUND};
  background-size: 100%;

  animation-name: ${animate};
  animation-duration: 1.5s;
  animation-delay: ${props => `${props.delay}s`};
  animation-timing-function: ease-in;
  animation-iteration-count: 1;
`;