expo/src/dom/webview/useDebugZeroHeight.ts

The Expo SDK

import { useState, useCallback } from 'react';
import { type ViewProps } from 'react-native';

import { type DOMProps, type WebViewProps } from '../dom.types';

type UseDebugZeroHeightType = (dom?: DOMProps) => {
  debugZeroHeightStyle: WebViewProps['containerStyle'] | undefined;
  debugOnLayout: ViewProps['onLayout'];
};

/**
 * Debug only hook to help identify zero height issues in the DOM component.
 */
export const useDebugZeroHeight: UseDebugZeroHeightType = __DEV__
  ? (dom) => {
      const [debugZeroHeightStyle, setDebugZeroHeightStyle] = useState<
        WebViewProps['containerStyle'] | undefined
      >(undefined);
      const [hasLoggedWarning, setHasLoggedWarning] = useState(false);

      const debugOnLayout = useCallback<NonNullable<ViewProps['onLayout']>>(
        (event) => {
          dom?.onLayout?.(event);
          if (dom?.matchContents) {
            return;
          }
          if (debugZeroHeightStyle !== undefined) {
            return;
          }
          if (event.nativeEvent.layout.height === 0) {
            if (!hasLoggedWarning) {
              console.warn(`
The DOM component has a zero height in native hierarchy.
We are adding a debug style to help you identify the issue.
You can remove this style by using the \`matchContents\` prop or explicitly add a height from the component callsite.
\`\`\`
<YourDomComponent dom={{ matchContents: true }} />
// or
<YourDomComponent dom={{ style: { height: 50 } }} />
\`\`\`
`);
              setHasLoggedWarning(true);
            }
            setDebugZeroHeightStyle({
              borderWidth: 1,
              borderColor: 'red',
              borderRadius: 2,
              minHeight: 40,
            });
          } else {
            setDebugZeroHeightStyle({});
          }
        },
        [dom?.matchContents, dom?.onLayout, debugZeroHeightStyle, hasLoggedWarning]
      );

      return { debugZeroHeightStyle, debugOnLayout };
    }
  : (dom) => ({
      debugZeroHeightStyle: undefined,
      debugOnLayout: dom?.onLayout,
    });