You can install the package via npm or yarn:

yarn add editorjs-color-picker

Alternatively, you can use the CDN version.

<script src="https://cdn.jsdelivr.net/npm/editorjs-color-picker@1.0.8/dist/index.umd.js"></script>

Add a new Tool to the tools property of the Editor.js initial config.

import ColorPicker from 'editorjs-color-picker';

const editor = new EditorJS({
  ...

  tools: {
    ...
    ColorPicker: {
      class: ColorPicker,
    },
  }

  ...
});

If you don't want the text to retain its colors every time you copy and paste it into the editor, you can use the ColorPickerWithoutSanitize class.

import { ColorPickerWithoutSanitize } from 'editorjs-color-picker';

const editor = new EditorJS({
  ...

  tools: {
    ...
    ColorPicker: {
      class: ColorPickerWithoutSanitize,
    },
  }

  ...
});

If you're using the CDN, you can access the tool via window.ColorPicker.default or window.ColorPicker.ColorPickerWithoutSanitize.

<script src="https://cdn.jsdelivr.net/npm/editorjs-color-picker@1.0.8/dist/index.umd.js"></script>

<script>
	const { ColorPicker } = window;
	const editor = new EditorJS({
	  ...

	  tools: {
	    ...
	    ColorPicker: {
	      class: ColorPicker.default,  // or ColorPicker.ColorPickerWithoutSanitize
	    },
	  }

	  ...
	});
</script>

The Paragraph Tool supports these configuration parameters:

If you copy and paste text with a different background color, it adopts the style of the <span>.
The only solution I’ve found so far, without modifying the paragraph component and its onPaste handler, is to apply this style.
For now, I’m only attaching it here without adding it to the library, as it might interfere with other plugins.
So, anyone interested should try applying this style:

.ce-paragraph span {
	background-color: unset !important;
}

If anyone finds a more elegant solution, can open a PR, and we’ll fix it.