@turf/line-slice/dist/esm/index.js

Useful for extracting only the part of a route between waypoints.

// index.ts
import { getCoords, getType } from "@turf/invariant";
import { lineString as linestring } from "@turf/helpers";
import { nearestPointOnLine } from "@turf/nearest-point-on-line";
function lineSlice(startPt, stopPt, line) {
  const coords = getCoords(line);
  if (getType(line) !== "LineString")
    throw new Error("line must be a LineString");
  const startVertex = nearestPointOnLine(line, startPt);
  const stopVertex = nearestPointOnLine(line, stopPt);
  fixSegmentIndexBounds(line, startVertex);
  fixSegmentIndexBounds(line, stopVertex);
  const ends = startVertex.properties.segmentIndex <= stopVertex.properties.segmentIndex ? [startVertex, stopVertex] : [stopVertex, startVertex];
  const clipCoords = [ends[0].geometry.coordinates];
  for (let i = ends[0].properties.segmentIndex + 1; i < ends[1].properties.segmentIndex + 1; i++) {
    clipCoords.push(coords[i]);
  }
  clipCoords.push(ends[1].geometry.coordinates);
  return linestring(clipCoords, line.type === "Feature" ? line.properties : {});
}
function fixSegmentIndexBounds(line, vertex) {
  let geometry = line.type === "Feature" ? line.geometry : line;
  if (vertex.properties.segmentIndex >= geometry.coordinates.length - 1) {
    vertex.properties.segmentIndex = geometry.coordinates.length - 2;
  }
}
var index_default = lineSlice;
export {
  index_default as default,
  lineSlice
};
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