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

   1 (function () {
   2   function GraphHopperEngine(modeId, vehicleType) {
   3     const GH_INSTR_MAP = {
   4       "-3": "sharp-left",
   5       "-2": "left",
   6       "-1": "slight-left",
   7       "0": "straight",
   8       "1": "slight-right",
   9       "2": "right",
  10       "3": "sharp-right",
  11       "4": "destination", // finish reached
  12       "5": "destination", // via reached
  13       "6": "roundabout",
  14       "-7": "fork-left",
  15       "7": "fork-right",
  16       "-98": "u-turn", // unknown direction u-turn
  17       "-8": "u-turn", // left u-turn
  18       "8": "u-turn" // 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] = "destination";
  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       mode: modeId,
  51       provider: "graphhopper",
  52       creditline: "<a href=\"https://www.graphhopper.com/\" target=\"_blank\">GraphHopper</a>",
  53       draggable: false,
  54
  55       getRoute: function (points, signal) {
  56         // GraphHopper Directions API documentation
  57         // https://graphhopper.com/api/1/docs/routing/
  58         const query = new URLSearchParams({
  59           vehicle: vehicleType,
  60           locale: I18n.currentLocale(),
  61           key: "LijBPDQGfu7Iiq80w3HzwB4RUDJbMbhs6BU0dEnn",
  62           elevation: false,
  63           instructions: true,
  64           turn_costs: vehicleType === "car"
  65         });
  66         points.forEach(p => query.append("point", p.lat + "," + p.lng));
  67         return fetch(OSM.GRAPHHOPPER_URL + "?" + query, { signal })
  68           .then(response => response.json())
  69           .then(({ paths }) => {
  70             if (!paths || paths.length === 0) throw new Error();
  71             return _processDirections(paths[0]);
  72           });
  73       }
  74     };
  75   }
  76
  77   OSM.Directions.addEngine(new GraphHopperEngine("car", "car"), true);
  78   OSM.Directions.addEngine(new GraphHopperEngine("bicycle", "bike"), true);
  79   OSM.Directions.addEngine(new GraphHopperEngine("foot", "foot"), true);
  80 }());