@googlemaps/google-maps-services-js
Version:
Node.js client library for Google Maps API Web Services
81 lines • 2.65 kB
JavaScript
;
/**
* Copyright 2020 Google LLC
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
Object.defineProperty(exports, "__esModule", { value: true });
exports.encodePath = encodePath;
exports.decodePath = decodePath;
/**
* Polyline encodes an array of LatLng objects.
*
* See {@link https://developers.google.com/maps/documentation/utilities/polylinealgorithm}
*
*/
function encodePath(path) {
const result = [];
let start = [0, 0];
let end;
const encodePart = function (part) {
part = part < 0 ? ~(part << 1) : part << 1;
while (part >= 0x20) {
result.push(String.fromCharCode((0x20 | (part & 0x1f)) + 63));
part >>= 5;
}
result.push(String.fromCharCode(part + 63));
};
for (let i = 0, I = path.length || 0; i < I; ++i) {
end = [Math.round(path[i].lat * 1e5), Math.round(path[i].lng * 1e5)];
encodePart(end[0] - start[0]); // lat
encodePart(end[1] - start[1]); // lng
start = end;
}
return result.join("");
}
/**
* Decodes a polyline encoded string.
*
* See {@link https://developers.google.com/maps/documentation/utilities/polylinealgorithm}
*/
function decodePath(encodedPath) {
const len = encodedPath.length || 0;
const path = new Array(Math.floor(encodedPath.length / 2));
let index = 0;
let lat = 0;
let lng = 0;
let pointIndex;
for (pointIndex = 0; index < len; ++pointIndex) {
let result = 1;
let shift = 0;
let b;
do {
b = encodedPath.charCodeAt(index++) - 63 - 1;
result += b << shift;
shift += 5;
} while (b >= 0x1f);
lat += result & 1 ? ~(result >> 1) : result >> 1;
result = 1;
shift = 0;
do {
b = encodedPath.charCodeAt(index++) - 63 - 1;
result += b << shift;
shift += 5;
} while (b >= 0x1f);
lng += result & 1 ? ~(result >> 1) : result >> 1;
path[pointIndex] = { lat: lat * 1e-5, lng: lng * 1e-5 };
}
path.length = pointIndex;
return path;
}
//# sourceMappingURL=util.js.map