使用嵌套的for和splice的Javascript

Question

I'm trying too look for points in a polygon.

So I have an array with point-objects and an array with polygon-objects.

I want to iterate over my points-array and than iterate over the polygon-array and look if the point is in that array. If the point is in the array I want to remove the point from the points-array because one point can only be in one polygon.

So I tried to use this function:

function pointsInPolygons(features, points) {
    var pointCopy = $.extend(true, [], points.features);
    for (var i = 0; i < pointCopy.length; i++) {
        var point = pointCopy[i];
        for (var j = 0; j < features.features.length; j++) {
            var feature = features.features[j];
            if (isPoly(feature) && gju.pointInPolygon(point.geometry, feature.geometry)) {
                feature.properties.ratings.push(point.properties.rating);
                pointCopy.splice(i, 1);
                i--;
            }
        }
    }
}

But after going through the inner for, the function is leaving. I tried the same without splice and decreasing i. But it is still the same behavior.

So the question is how can I get into the outer for again?

Answer 1

Actually, you don't have to remove the item from the array, your current for loop against points will only iterate through once. Here's a flatten approach to what you're doing.

function pointsInPolygons(features, points){
  let pointsCopy = points.features.slice();
  let check = (point,feature) => isPoly(feature) && gju.pointInPolygon(point.geometry, feature.geometry);
  let isInPolygon = point => features.find(check.bind(null, point));

  pointsCopy.forEach(point => {
    let feature = isInPolygon(point);
    if (!!feature) {
      feature.properties.ratings.push(point.properties.rating);
    }
  });
}