wagtail-deprecated / react-streamfield

Powerful field for inserting multiple blocks with nesting. (NO LONGER MAINTAINED - See Wagtail 2.13 Release Notes)

⚠️ No longer maintained: Features have been merged into Wagtail see 2.13 Release Notes.

React StreamField

Powerful field for inserting multiple blocks with nesting.

Originally created for the Wagtail CMS thanks to a Kickstarter campaign.

Demo

https://wagtail.github.io/react-streamfield/public/

Example usage

To have an idea on how to fully integrate react-streamfield, please check this CodeSandbox demo.

For more complex examples, see example/index.story.js and the corresponding demos for more complex examples.

More documentation will arrive soon!

You can also check out wagtail-react-streamfield to see what an integration of this field looks like!

Internet Explorer 11 support

These JavaScript features are used in react-streamfield that are not supported natively in Internet Explorer 11:

• Element.closest(…)
• Array.find(…)
• Object.entries(…)
• CustomEvent

When using react-streamfield for Internet Explorer 11, you need to include the polyfills found in the section below, otherwise the package will not work properly.

Polyfills

React-streamfield uses some JavaScript features only available starting ECMAScript 2015. Some of these features are not handled by browsers such as Internet Explorer 11.

To maintain compatibility when using react-streamfield, install and import these polyfills (a polyfill adds a missing JavaScript browser feature):

{
  "dependencies": {
    "core-js": "^2.6.5",
    "element-closest": "^3.0.1",
    "custom-event-polyfill": "^1.0.6"
  }
}

import 'core-js/shim'
import 'element-closest';
import 'custom-event-polyfill';

Webpack stats

https://wagtail.github.io/react-streamfield/public/webpack-stats.html

react-streamfield's Issues

Issue with nested StructBlock

An issue arose when I have a StructBlock inside a StructBlock.

Check out my example "Nested struct block" at https://roelio.github.io/react-streamfield/example/
you can see that the inner struct block is handles as a list.

:focus-within may drop some styles in IE 11 + Edge

I happened across this article today:

https://catalin.red/fancy-new-selectors-can-break-your-css-rule/

Yet to have a chance to test this, but we do use :focus-within in a couple of places in c-sf-block.scss so should consider using JS instead or at least forcing it to be a separate selector so it only drops the :focus-within styles and not the :hover :focus too.

Code review

Alright! 🙂 I generally don't have the chance to review a whole package, that was a lot of fun. In the end I tried to be as exhaustive as possible with my comments, but a lot of it is fairly minor / quick to address.

I made the review as a pull request that contains all of the package's code, over at thibaudcolas#1, so it would be easier to relate comments to code. But I also summarised most of the comments below, so they are easier to relate to one another, and prioritise. It's probably easier to first read this list, then the comments in the PR.

I also made a PR to address some of the issues below (packaging, dev tools, and API), over at #5, along with the corresponding changes to Wagtail in a branch that builds upon wagtail/wagtail#4942.

Potential problems

These are the code-level problems I would expect to cause the most pain / actual bugs. They are ordered by how important I think they are to address sooner rather than later.

• Make an API for the package instead of doing the Wagtail integration in it (thibaudcolas#1 (comment), thibaudcolas#1 (comment))
• Overly generic class names across all of the UI (e.g. icon, field, required)  – these should use BEM, and-or be namespaced (see "Styles" section below, and thibaudcolas#1 (comment), thibaudcolas#1 (comment), thibaudcolas#1 (comment), thibaudcolas#1 (comment), thibaudcolas#1 (comment), thibaudcolas#1 (comment), thibaudcolas#1 (comment))
• Do not use elements like aside, article, header. They provide no semantic value for a form / widget like StreamField (thibaudcolas#1 (comment))
• AddButton's groupedBlockDefinitions – What happens if key is an empty string? It seems like this is going to override the groups (thibaudcolas#1 (comment))
• extractText – Use either textContent or innerText depending on the desired outcome (thibaudcolas#1 (comment))
• Add CustomEvent polyfill to Wagtail for IE11 support, or change the code not to need it (thibaudcolas#1 (comment))
• Add an API for Wagtail to provide translations (thibaudcolas#1 (comment))
• Button labels should be provided by Wagtail, so they are localised instead of english-only (thibaudcolas#1 (comment))
• Disabled buttons in block actions should be disabled with the corresponding HTML attribute rather than CSS (thibaudcolas#1 (comment))
• Replace deprecated initEvent with event constructor (thibaudcolas#1 (comment))
• Move StreamField constructor side-effects to componentDidMount (see react-redux section below) (thibaudcolas#1 (comment))
• See whole "Packaging" section below

Performance

• Revisit the AnimateHeight implementations to only render their children to the DOM when they are meant to be displayed (AddButton's panel, Block children) (thibaudcolas#1 (comment), thibaudcolas#1 (comment), thibaudcolas#1 (comment))
• Clean up listeners / observers set up in RawHtmlFieldInput componentDidMount, which can cause memory leaks (thibaudcolas#1 (comment))
• Small thing – do not render the add panel's group name if it's an empty string (thibaudcolas#1 (comment))

Error handling

Generally I haven't seen much error handling code. I would expect the inner script execution to be the most problematic, since it will be very common for third-party code to break.

• Add error handling to inner script execution (thibaudcolas#1 (comment))
• Add error handling to RawHtmlFieldInput's componentDidMount (thibaudcolas#1 (comment))
• Add error handling of moveBlock action (thibaudcolas#1 (comment))
• Ideally, add error handling to all of StreamField (componentDidCatch?) for unforeseen sources of error

Minor ones

Minor but still sources of concern

• Preserve script tags in inner script execution instead of using eval (thibaudcolas#1 (comment))
• <BlocksContainer /> isn't valid HTML. We shouldn't encourage people to write HTML that doesn't pass validation. For a semantic-free token/placeholder, use a noscript tag with a data attribute. (thibaudcolas#1 (comment), thibaudcolas#1 (comment))
• getIsMobile – Use window.matchMedia to make sure the JS and CSS breakpoint definitions are in sync (thibaudcolas#1 (comment))

---

Packaging - build & dependenceies

The general problem here is that the library is compiled as if it was an app, instead of a library, with all of its dependencies bundled instead of resolved by npm on install.

• Stop bundling dependencies in the compiled/published code, these should be resolved as part of the dependency management and build of the consumer code (Wagtail’s) (thibaudcolas#1 (comment))
• Publish the package as both CommonJS and ES modules, with main and module attributes in package.json (thibaudcolas#1 (comment))
• Remove any side effects on import, and mark the package as "sideEffects": false, for Webpack consumers (thibaudcolas#1 (comment))
• Expose the compiled source (dist) via npm only, not in version control (thibaudcolas#1 (comment))
• Consider using Rollup instead of Webpack to achieve all of the above easily (thibaudcolas#1 (comment))
• Do not pin dependencies to exact versions in package.json. Instead, use a package-lock.json. (thibaudcolas#1 (comment))
• Move non-dev dependencies to dependencies: classnames, react-animate-height, react-beautiful-dnd, uuid (react-redux, redux, redux-thunk, react, react-dom, prop-types) (thibaudcolas#1 (comment))
• Move most fundamental and heavy dependencies to peerDependencies: react-redux, redux, redux-thunk, react, react-dom, prop-types (thibaudcolas#1 (comment), thibaudcolas#1 (comment))

Bonus points

• Consider using sass (official Dart implementation) to get rid of the annoying native code compilation of node-sass. (thibaudcolas#1 (comment))
• Consider configuring transform-react-remove-prop-types to wrap proptypes instead of removing them, as for a project like this they can be very useful in dev mode. (thibaudcolas#1 (comment))
• Remove unused @babel/cli (thibaudcolas#1 (comment))
• Consider replacing @babel/plugin-proposal-decorators and decorators syntax with normal higher-order functions/components. (thibaudcolas#1 (comment))

Documentation

To me this is what would be the most worthy of documentation. The blockDefinitions schema is probably this package’s most important API, and the polyfills are its least obvious requirements.

• Document the blockDefinitions schema (can be as simple as adding comments to BlockDefinitionType, and linking to this) (thibaudcolas#1 (comment))
• Document the need for a position: sticky polyfill in the project's README, and in https://docs.wagtail.io/en/v2.4/contributing/developing.html?highlight=Sticky (Wagtail doesn't come with one, it's very expensive perf-wise), for full IE11 support (thibaudcolas#1 (comment))
• Document the need for the element-closest polyfill for IE11 support (thibaudcolas#1 (comment))
• Document the need for the Array#find polyfill for IE11 support (thibaudcolas#1 (comment))
• Document the need for the Object#entries polyfill for IE11 support (thibaudcolas#1 (comment))
• Document the need for the CustomEvent polyfill for IE11 support (thibaudcolas#1 (comment))

Development & demo env

• Consider setting up linting with ESLint and Stylelint, with a config similar to that of Wagtail (thibaudcolas#1 (comment))
• Consider setting up Prettier for automated formatting (thibaudcolas#1 (comment))
• Consider swithing to Storybook for a better dev / demo environment (thibaudcolas#1 (comment))
• Consider removing drop_console setting from UglifyJS setup (thibaudcolas#1 (comment))
• Consider using SVG instead of FontAwesome for the icons (thibaudcolas#1 (comment))
• Add Autoprefixer to the CSS build (Wagtail already has it, so this is just about having a similar setup for this package’s dev/demo site, so it can be used for cross-browser testing) (thibaudcolas#1 (comment))
• Consider adding an example with a custom JS widget (thibaudcolas#1 (comment))

Styles

• Split src/index.scss into multiple files, ideally following the separation between React components (one styles file per component) (thibaudcolas#1 (comment))
• Use BEM notation for element selectors, e.g. .add-block-button instead of button.add (thibaudcolas#1 (comment), thibaudcolas#1 (comment))
• Use BEM notation for state selectors, e.g. .children-container--dragging instead of .children-container.is-dragging (thibaudcolas#1 (comment), thibaudcolas#1 (comment), thibaudcolas#1 (comment))
• Replace bare element names by class names, e.g. .block-header instead of header (thibaudcolas#1 (comment), thibaudcolas#1 (comment))
• Consider using a JS-added --focus class instead of :focus-within, if the functionality is important enough (thibaudcolas#1 (comment))

Accessibility

I'm sure the current StreamField implementation isn't particularly SR-friendly, so we're not aiming super high, but there are obvious improvements to be made here.

• AddButton’s + icon should have a text-only label for screen reader users (thibaudcolas#1 (comment))
• All other icons should also have text-only labels for screen reader users (thibaudcolas#1 (comment))
• All icons should be marked as aria-hidden="true" so screen readers ignore them (thibaudcolas#1 (comment), thibaudcolas#1 (comment))
• All icons should be built with SVG instead of an icon font (thibaudcolas#1 (comment))

react-redux

react-redux recently released its v6, which uses the new React context API from React 16.4, and introduces a change in behavior that affects this package:

[...] there is a behavior change around dispatching actions in constructors / componentWillMount. Previously, dispatching in a parent component's constructor would cause its children to immediately use the updated state as they mounted, because each component read from the store individually. In version 6, all components read the same current store state value from context, which means the tree will be consistent and not have "tearing". This is an improvement overall, but there may be applications that relied on the existing behavior.

This is the problematic code:

https://github.com/noripyt/react-streamfield/blob/9b720dd715140f5c931560e75431ea472600f9be/src/StreamField.js#L95-L107

The consequence is that BlocksContainer will fail to render because it does not expect to have access to an uninitialised state. It's generally not recommended to have side-effects in the constructor anyway, moving this init to componentDidMount would make the problem even more obvious.

I can see a few solutions:

• Move the initializeStreamField logic out of StreamField, to be done when the store is created
• Move initializeStreamField call to componentDidMount, and do not render the BlockContainer until initialisation is over.

Anyway, it's not necessary to upgrade to v6 now. I also have two concerns with the upgrade:

• react-beautiful-dnd also uses Redux and react-redux v5, but doesn't declare them as peerDependencies. Using different versions from it would mean they get bundled twice for end users, which I would rather avoid. From memory Redux is fairly small in size, but react-redux is a good 20kb.
• Wagtail uses v5, and switching to v6 will require updating Wagtail's code. Shouldn't be a big deal, but it will take a bit of time.

---

Finally on the react-redux front, I'm surprised that all/most of the components in the package are connected. I would expect the performance to be better if some of the connections were removed, as they clearly duplicate their computation (but use PureComponent or React.memo to still have the same rendering performance)

• Remove connection of BlockContent, and use props from Block instead (thibaudcolas#1 (comment))
• Remove connection of BlockHeader, and use props from Block instead (thibaudcolas#1 (comment))
• Remove connection of BlockActions, and use props from Block instead (thibaudcolas#1 (comment))
• Remove connection of RawHtmlFieldInput, and use props from FieldInput instead (thibaudcolas#1 (comment))

This would also make it easier to write tests for those components, which I would really like to see.

Smaller JS / React things

• Consider using updater callbacks for setState calls such as this.setState({open: !this.state.open}); (thibaudcolas#1 (comment))
• Consider binding the addHandler's key to the function, instead of storing it and reading it in HTML. (thibaudcolas#1 (comment))
• It's more idiomatic to check for null/undefined ("falsey") values by doing if (value) instead of if (value === null), value !== undefined (thibaudcolas#1 (comment), thibaudcolas#1 (comment), thibaudcolas#1 (comment))
• There are other idiomatic JS comments I've added along the way.
• Consider using the latest syntax for React fragments (<></>) (thibaudcolas#1 (comment))
• Remove unneeded boolean parameter of getDescendantsIds (always called with true) (thibaudcolas#1 (comment))
• Split getNewBlock of the utils into smaller functions (thibaudcolas#1 (comment))
• Remove unneeded prefixed fallbacks for MutationObserver (thibaudcolas#1 (comment))
• Do not use h3 for BlockHeader's icon (thibaudcolas#1 (comment))
• Extract block title rendering logic, and add tests for it (thibaudcolas#1 (comment))
• Use a switch statement for the reducer (thibaudcolas#1 (comment))
• Rename actions.js to reducers.js (thibaudcolas#1 (comment))
• Unneeded deepCopy? (thibaudcolas#1 (comment))
• Use FSA for actions like Wagtail (thibaudcolas#1 (comment))

Helping out with the react-streamfield

Hi @BertrandBordage,

We are extending the react-streamfield on https://github.com/stamkracht/react-streamfield. Already did some minor updates that gives us a bit more control through the blockDefinitions. We are manipulating the blockDefinition through get_definition so we didn't need todo any Python changes yet.

I've seen the RFC and a lot of it is stuff we can also use and I wonder if we can help you achieving those features? We have a lot of in-house experience with both Python and JS. It would be a shame if we do the same stuff but slightly different, so maybe you can give your thoughts on this.

prettier-stylelint should be in devDependencies

In the project’s package.json, prettier-stylelint is defined in dependencies: https://github.com/wagtail/react-streamfield/blob/b13b41fd382445bd5fe1ebb63224bdfa0007e219/package.json#L35-L41.

This is problematic as it pollutes every codebase that react-streamfield is installed in, unnecessarily installing a lot of extra dependencies.

`c-sf-add-button--closed` classname should be `--close`

The --closed classname defined here:

https://github.com/wagtail/react-streamfield/blob/e775cd303323daabc6de824d23b1d74d6cb35354/src/scss/components/c-sf-add-button.scss#L36

would be better named --close, as it defines the style for a close button which appears when the panel is open.

Fixing this would mean that we can avoid the back-to-front logic of {% if state == 'open' %}c-sf-add-button--closed{% endif %} in wagtail/wagtail#5476 :-)