app/assets/javascripts/index/directions/graphhopper.js

   1 (function () {
   2   function GraphHopperEngine(id, vehicleType) {
   3     const GH_INSTR_MAP = {
   4       "-3": 7, // sharp left
   5       "-2": 6, // left
   6       "-1": 5, // slight left
   7       "0": 0, // straight
   8       "1": 1, // slight right
   9       "2": 2, // right
  10       "3": 3, // sharp right
  11       "4": 14, // finish reached
  12       "5": 14, // via reached
  13       "6": 10, // roundabout
  14       "-7": 19, // keep left
  15       "7": 18, // keep right
  16       "-98": 4, // unknown direction u-turn
  17       "-8": 4, // left u-turn
  18       "8": 4 // right u-turn
  19     };
  20
  21     function _processDirections(path) {
  22       const line = L.PolylineUtil.decode(path.points);
  23
  24       const steps = path.instructions.map(function (instr, i) {
  25         const num = `<b>${i + 1}.</b> `;
  26         const lineseg = line
  27           .slice(instr.interval[0], instr.interval[1] + 1)
  28           .map(([lat, lng]) => ({ lat, lng }));
  29         return [
  30           lineseg[0],
  31           GH_INSTR_MAP[instr.sign],
  32           num + instr.text,
  33           instr.distance,
  34           lineseg
  35         ]; // TODO does graphhopper map instructions onto line indices?
  36       });
  37       steps.at(-1)[1] = 14;
  38
  39       return {
  40         line: line,
  41         steps: steps,
  42         distance: path.distance,
  43         time: path.time / 1000,
  44         ascend: path.ascend,
  45         descend: path.descend
  46       };
  47     }
  48
  49     return {
  50       id: id,
  51       creditline: "<a href=\"https://www.graphhopper.com/\" target=\"_blank\">GraphHopper</a>",
  52       draggable: false,
  53
  54       getRoute: function (points, signal) {
  55         // GraphHopper Directions API documentation
  56         // https://graphhopper.com/api/1/docs/routing/
  57         const query = new URLSearchParams({
  58           vehicle: vehicleType,
  59           locale: I18n.currentLocale(),
  60           key: "LijBPDQGfu7Iiq80w3HzwB4RUDJbMbhs6BU0dEnn",
  61           elevation: false,
  62           instructions: true,
  63           turn_costs: vehicleType === "car"
  64         });
  65         points.forEach(p => query.append("point", p.lat + "," + p.lng));
  66         return fetch(OSM.GRAPHHOPPER_URL + "?" + query, { signal })
  67           .then(response => response.json())
  68           .then(({ paths }) => {
  69             if (!paths || paths.length === 0) throw new Error();
  70             return _processDirections(paths[0]);
  71           });
  72       }
  73     };
  74   }
  75
  76   OSM.Directions.addEngine(new GraphHopperEngine("graphhopper_car", "car"), true);
  77   OSM.Directions.addEngine(new GraphHopperEngine("graphhopper_bicycle", "bike"), true);
  78   OSM.Directions.addEngine(new GraphHopperEngine("graphhopper_foot", "foot"), true);
  79 }());