react-instantsearch/packages/react-instantsearch-dom-maps/src/Provider.js

import React, { Component } from 'react';
import PropTypes from 'prop-types';
import { LatLngPropType, BoundingBoxPropType } from './propTypes';
import GeoSearchContext from './GeoSearchContext';

class Provider extends Component {
  static propTypes = {
    google: PropTypes.object.isRequired,
    hits: PropTypes.arrayOf(PropTypes.object).isRequired,
    isRefineOnMapMove: PropTypes.bool.isRequired,
    hasMapMoveSinceLastRefine: PropTypes.bool.isRequired,
    isRefineEnable: PropTypes.bool.isRequired,
    refine: PropTypes.func.isRequired,
    toggleRefineOnMapMove: PropTypes.func.isRequired,
    setMapMoveSinceLastRefine: PropTypes.func.isRequired,
    children: PropTypes.func.isRequired,
    position: LatLngPropType,
    currentRefinement: BoundingBoxPropType,
  };

  isPendingRefine = false;
  boundingBox = null;
  previousBoundingBox = null;

  refineWithInstance = (instance) => {
    const { refine } = this.props;

    const bounds = instance.getBounds();

    refine({
      northEast: bounds.getNorthEast().toJSON(),
      southWest: bounds.getSouthWest().toJSON(),
    });
  };

  mapValue = {
    isRefineOnMapMove: this.props.isRefineOnMapMove,
    hasMapMoveSinceLastRefine: this.props.hasMapMoveSinceLastRefine,
    toggleRefineOnMapMove: this.props.toggleRefineOnMapMove,
    setMapMoveSinceLastRefine: this.props.setMapMoveSinceLastRefine,
    refineWithInstance: this.refineWithInstance,
  };

  getMapValue = () => {
    const haveContextValuesChanges =
      this.mapValue.isRefineOnMapMove !== this.props.isRefineOnMapMove ||
      this.mapValue.hasMapMoveSinceLastRefine !==
        this.props.hasMapMoveSinceLastRefine;

    if (haveContextValuesChanges) {
      this.mapValue = {
        ...this.mapValue,
        isRefineOnMapMove: this.props.isRefineOnMapMove,
        hasMapMoveSinceLastRefine: this.props.hasMapMoveSinceLastRefine,
      };
    }

    return this.mapValue;
  };

  createBoundingBoxFromHits(hits) {
    const { google } = this.props;

    const latLngBounds = hits.reduce(
      (acc, hit) => acc.extend(hit._geoloc),
      new google.maps.LatLngBounds()
    );

    return {
      northEast: latLngBounds.getNorthEast().toJSON(),
      southWest: latLngBounds.getSouthWest().toJSON(),
    };
  }

  onChange = () => {
    const { isRefineOnMapMove, isRefineEnable, setMapMoveSinceLastRefine } =
      this.props;

    if (isRefineEnable) {
      setMapMoveSinceLastRefine(true);

      if (isRefineOnMapMove) {
        this.isPendingRefine = true;
      }
    }
  };

  onIdle = ({ instance }) => {
    if (this.isPendingRefine) {
      this.isPendingRefine = false;

      this.refineWithInstance(instance);
    }
  };

  shouldUpdate = () => {
    const { hasMapMoveSinceLastRefine } = this.props;

    return !this.isPendingRefine && !hasMapMoveSinceLastRefine;
  };

  render() {
    const { hits, currentRefinement, children } = this.props;

    // We use this value for differentiate the padding to apply during
    // fitBounds. When we don't have a currenRefinement (boundingBox)
    // we let GoogleMaps compute the automatic padding. But when we
    // provide the currentRefinement we explicitly set the padding
    // to `0` otherwise the map will decrease the zoom on each refine.
    const boundingBoxPadding = !currentRefinement ? undefined : 0;
    const boundingBox =
      !currentRefinement && Boolean(hits.length)
        ? this.createBoundingBoxFromHits(hits)
        : currentRefinement;

    return (
      <GeoSearchContext.Provider value={this.getMapValue()}>
        {children({
          onChange: this.onChange,
          onIdle: this.onIdle,
          shouldUpdate: this.shouldUpdate,
          boundingBox,
          boundingBoxPadding,
        })}
      </GeoSearchContext.Provider>
    );
  }
}

export default Provider;