corygibbons / component-image

📷 Generate image snapshots of React components for visual regression testing

Component Image

Generate image snapshots of React components for visual regression testing. This package will only give you the image, you'll have to diff it with something else (like jest-image-snapshot).

Usage

Install

npm install component-image

Use

import { generateImage } from 'component-image';

generateImage(component, options);

Default options

options = {
  // Path to .css file
  stylesheet: undefined;
  // Change size of screenshot
  viewport: {
    width: 800,
    height: 600,
  },
  renderer: ReactDOMServer.renderToStaticMarkup,
  image: {
    // Path to save image, likely unnecessary
    path: undefined,
  },
  // Options that are passed to Puppeteer
  puppeteerOptions: {}
}

Integration Example

Usage with jest-image-snapshot:

import React from 'react';
import { generateImage } from 'component-image'

const component = (
  <div>
    <h1>The Component</h1>
  </div>
);

describe('Test Component', () => {
  it('has no visual regressions', () => {

    return generateImage(component, {
      stylesheet: '../../style.css',
      viewport: {
        width: 1000,
        height: 860
      }
    }).then(image => {
      expect(image).toMatchImageSnapshot();
    });

  };
};

component-image's Issues

Set delay before taking screenshot?

I'm working with a legacy component (that is itself a legacy D3 chart shoved into a React component and hacked together using refs). I'm unable to use component-image on it because the initial element is added to the DOM in the first run of render, but is not actually populated with a graph until componentDidMount runs. Therefore, I'm getting a blank screenshot.

Before I just bite the bullet and rewrite this crap (referring to my component), is there any way to set a small delay?

Fonts imported with @import are not loaded

I have fonts imported with CSS @import but the fonts are not in use in the generated image.

CSS:

@import url('https://fonts.googleapis.com/css?family=Merriweather');
h1 {
  font-family: 'Merriweather';
}

When I generate image with React component <h1>AaBbCc</h1> the imported font is not visible in the image.

Not able to render background image and fonts specified in css in screenshot

Hi @corygibbons,

I started using this lib for image comparision tests. My css has fonts and background images in it but while taking the screenshot both are missing. However normal static css is working fine. Can help with this?

my css looks like this:

.my_background_img {
background: url('placeholderimage.png') no-repeat;
}

this background is not getting applied in the html but all other css is getting applied.

Cannot find ws when generating component to image

When I try to export standard component like shown in tutorial using generateImage function it's showing error Module not found: Can't resolve 'ws' in /node_modules/puppeteer/lib

Styled Components

Does this work with styled components? I tried providing the path to my styled component for stylesheet but the style doesn't get loaded.