@globalfishingwatch/react-map-gl/dist/es6/components/layer.js

A React wrapper for MapboxGL-js and overlay API.

import { useContext, useEffect, useMemo, useState, useRef } from 'react';
import PropTypes from 'prop-types';
import MapContext from './map-context';
import assert from '../utils/assert';
import deepEqual from '../utils/deep-equal';
const LAYER_TYPES = {
  fill: 'fill',
  line: 'line',
  symbol: 'symbol',
  circle: 'circle',
  'fill-extrusion': 'fill-extrusion',
  raster: 'raster',
  background: 'background',
  heatmap: 'heatmap',
  hillshade: 'hillshade'
};
const propTypes = {
  type: PropTypes.oneOf(Object.keys(LAYER_TYPES)).isRequired,
  id: PropTypes.string,
  source: PropTypes.string,
  beforeId: PropTypes.string
};

function diffLayerStyles(map, id, props, prevProps) {
  const {
    layout = {},
    paint = {},
    filter,
    minzoom,
    maxzoom,
    beforeId,
    ...otherProps
  } = props;

  if (beforeId !== prevProps.beforeId) {
    map.moveLayer(id, beforeId);
  }

  if (layout !== prevProps.layout) {
    const prevLayout = prevProps.layout || {};

    for (const key in layout) {
      if (!deepEqual(layout[key], prevLayout[key])) {
        map.setLayoutProperty(id, key, layout[key]);
      }
    }

    for (const key in prevLayout) {
      if (!layout.hasOwnProperty(key)) {
        map.setLayoutProperty(id, key, undefined);
      }
    }
  }

  if (paint !== prevProps.paint) {
    const prevPaint = prevProps.paint || {};

    for (const key in paint) {
      if (!deepEqual(paint[key], prevPaint[key])) {
        map.setPaintProperty(id, key, paint[key]);
      }
    }

    for (const key in prevPaint) {
      if (!paint.hasOwnProperty(key)) {
        map.setPaintProperty(id, key, undefined);
      }
    }
  }

  if (!deepEqual(filter, prevProps.filter)) {
    map.setFilter(id, filter);
  }

  if (minzoom !== prevProps.minzoom || maxzoom !== prevProps.maxzoom) {
    map.setLayerZoomRange(id, minzoom, maxzoom);
  }

  for (const key in otherProps) {
    if (!deepEqual(otherProps[key], prevProps[key])) {
      map.setLayerProperty(id, key, otherProps[key]);
    }
  }
}

function createLayer(map, id, props) {
  if (map.style && map.style._loaded) {
    const options = { ...props,
      id
    };
    delete options.beforeId;
    map.addLayer(options, props.beforeId);
  }
}

function updateLayer(map, id, props, prevProps) {
  assert(props.id === prevProps.id, 'layer id changed');
  assert(props.type === prevProps.type, 'layer type changed');

  try {
    diffLayerStyles(map, id, props, prevProps);
  } catch (error) {
    console.warn(error);
  }
}

let layerCounter = 0;

function Layer(props) {
  const context = useContext(MapContext);
  const propsRef = useRef({
    id: props.id,
    type: props.type
  });
  const [, setStyleLoaded] = useState(0);
  const id = useMemo(() => props.id || "jsx-layer-".concat(layerCounter++), []);
  const {
    map
  } = context;
  useEffect(() => {
    if (map) {
      const forceUpdate = () => setStyleLoaded(version => version + 1);

      map.on('styledata', forceUpdate);
      return () => {
        map.off('styledata', forceUpdate);

        if (map.style && map.style._loaded) {
          map.removeLayer(id);
        }
      };
    }

    return undefined;
  }, [map]);
  const layer = map && map.style && map.getLayer(id);

  if (layer) {
    updateLayer(map, id, props, propsRef.current);
  } else {
    createLayer(map, id, props);
  }

  propsRef.current = props;
  return null;
}

Layer.propTypes = propTypes;
export default Layer;
//# sourceMappingURL=layer.js.map