CSS Emotion Library - Getting css props error when using css prop

Question

This is my code

import { css, jsx } from '@emotion/core'
       
return (
       <>
       <img css={css`height: 200px; height: 200px;`} fluid={image.sharp.fluid} />
       <List>
           <li>Our Clients</li>
           <li>What We Do</li>
           <li>Contact</li>
       </List>
       </>
   )

This is the error I'm getting

You have tried to stringify object returned from css function. It isn't supposed to be used directly (e.g. as value of the className prop), but rather handed to emotion so it can handle it (e.g. as value of css prop).

This error seems to be telling me that I need to do what I am already doing? Or am I missing something here.

Answer 1

As detailed in the Emotion documentation, use of the css prop requires you replace React with jsx as the target function for JSX elements (known as the “pragma”), which will enable Emotion to intercept the css prop and transform it into a className prop for React.

For example:

<p>Hi</p>

// Becomes the following by default:
React.createElement("p", {}, "Hi")

// But with the `jsx` pragma, it becomes:
jsx("p", {}, "Hi")

There are two outlined approaches to achieve this. You only need to select one. If you are able to configure Babel in your application, the first is the recommended approach, but either one works fine:

1. Install a Babel plugin that will configure jsx as the default handler for all code in your app

   The most direct way to do this is by adding the relevant Babel preset to your Babel configuration like so:

   // Option 1A — Good
   // Add @emotion/babel-preset-css-prop to your dev dependencies, then
   // add the preset to your .babelrc configuration:
   
   {
     "presets": ["@emotion/babel-preset-css-prop"]
   }
   

   If you are able to do this, though, I recommend instead configuring babel-plugin-emotion, which includes the css prop configuration as well other features like minification, dead code elimination, and hoisting:

   // Option 1B — Better
   // Add babel-plugin-emotion to your dev dependencies, then add
   // the plugin to your Babel configuration (e.g. .babelrc)
   {
     "plugins": ["emotion"]
   }
   

2. Import the jsx function from Emotion and instruct Babel to use this imported function on a per-file basis using pragma

   /** @jsx jsx */
   import { jsx } from '@emotion/core'
   

Answer 2

In addition to include the @emotion/babel-plugin, there was some configuration that I have missed that created that error.

{
  "presets": [
    [
      "@babel/preset-react",
      { "runtime": "automatic", "importSource": "@emotion/react" }
    ]
  ],
  "plugins": ["@emotion/babel-plugin"]
}

The "importSource": "@emotion/react" was missing. After adding it, the error was gone and the styles were implemented correc5y.

Answer 3

Just wanted to note I had this issue and adding this fixed the error for me:

/** @jsx jsx */
import { jsx } from '@emotion/core';

Just to clarify, you have to add /** @jsx jsx */; at the top of the file.

Answer 4

This method solved my problem:

/** @jsxImportSource @emotion/react */
import { css } from "@emotion/react"

export default function somepage() {

  const color = 'red'

  return (<div
    css={css`
      background-color: hotpink;
      &:hover {
        color: ${color};
      }
    `}
  >
    Hello World.
  </div>)
}