Layer

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Layers allow you to render children outside the DOM hierarchy of the parent. It's a wrapper around React createPortal that lets you use it as a component. This is particularly useful for places you might have needed to use z-index to overlay the screen before.

Props

Name	Type	Default
`children` Required	`React.Node`	-
`zIndex`	`interface Indexable { index(): number; }`	-
	An object representing the zIndex value of the Layer.

Server Rendering

Because creating a portal in Layer depends on DOM manipulation, if document is not present, such as in a server rendering environment, the children will not be rendered.

Overlaying Content

Child content will be rendered outside the DOM hierarchy for easy overlaying. Click to see an example.

function Example() {

  const [showLayer, setShowLayer] = React.useState(false);

  return (
    <React.Fragment>
      <Button
        text="Show Layer"
        onClick={() => setShowLayer(!showLayer)}
      />
      {showLayer && (
        <Layer>
          <Box color="darkWash" position="fixed" top left right bottom display="flex" alignItems="center" justifyContent="center">
            <Box color="white" padding={3} display="flex" alignItems="center">
              <Text>Layer Content</Text>
              <Box marginStart={2}>
                <IconButton
                  accessibilityLabel="Close"
                  icon="cancel"
                  onClick={() => setShowLayer(!showLayer)}
                />
              </Box>
            </Box>
          </Box>
        </Layer>
      )}
    </React.Fragment>
  );
}

function Example() {
  const [showLayer, setShowLayer] = React.useState(false);
  return (
    <React.Fragment>
      <Button
        text="Show Layer"
        onClick={() => setShowLayer(!showLayer)}
      />
      {showLayer && (
        <Layer>
          <Box color="darkWash" position="fixed" top left right bottom display="flex" alignItems="center" justifyContent="center">
            <Box color="white" padding={3} display="flex" alignItems="center">
              <Text>Layer Content</Text>
              <Box marginStart={2}>
                <IconButton
                  accessibilityLabel="Close"
                  icon="cancel"
                  onClick={() => setShowLayer(!showLayer)}
                />
              </Box>
            </Box>
          </Box>
        </Layer>
      )}
    </React.Fragment>
  );
}

zIndex

The example below shows using a `FixedZIndex` for the header zIndex and a `CompositeZIndex` to stack the Layer on top of it. Visit our Z-Index documentation for more details on how to use these utility classes.

function zIndexExample() {
  const [showLayer, setShowLayer] = React.useState(false);
  const HEADER_ZINDEX = new FixedZIndex(100);
  // Results in a zIndex of 101
  const zIndex = new CompositeZIndex([HEADER_ZINDEX]);

  return (
    <React.Fragment>
      <Button
        text="Show Layer"
        onClick={() => setShowLayer(!showLayer)}
      />
      {showLayer && (
        <Layer zIndex={zIndex}>
          <Box color="darkWash" position="fixed" top left right bottom display="flex" alignItems="center" justifyContent="center">
            <Box color="white" padding={3} display="flex" alignItems="center">
              <Text>Layer Content</Text>
              <Box marginStart={2}>
                <IconButton
                  accessibilityLabel="Close"
                  icon="cancel"
                  onClick={() => setShowLayer(!showLayer)}
                />
              </Box>
            </Box>
          </Box>
        </Layer>
      )}
    </React.Fragment>
  );
}

function zIndexExample() {
  const [showLayer, setShowLayer] = React.useState(false);
  const HEADER_ZINDEX = new FixedZIndex(100);
  // Results in a zIndex of 101
  const zIndex = new CompositeZIndex([HEADER_ZINDEX]);
  return (
    <React.Fragment>
      <Button
        text="Show Layer"
        onClick={() => setShowLayer(!showLayer)}
      />
      {showLayer && (
        <Layer zIndex={zIndex}>
          <Box color="darkWash" position="fixed" top left right bottom display="flex" alignItems="center" justifyContent="center">
            <Box color="white" padding={3} display="flex" alignItems="center">
              <Text>Layer Content</Text>
              <Box marginStart={2}>
                <IconButton
                  accessibilityLabel="Close"
                  icon="cancel"
                  onClick={() => setShowLayer(!showLayer)}
                />
              </Box>
            </Box>
          </Box>
        </Layer>
      )}
    </React.Fragment>
  );
}

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