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var average = require('turf-average')
var sum = require('turf-sum')
var median = require('turf-median')
var min = require('turf-min')
var max = require('turf-max')
var deviation = require('turf-deviation')
var variance = require('turf-variance')
var count = require('turf-count')
var turf = {}
turf.average = average
turf.sum = sum
turf.median = median
turf.min = min
turf.max = max
turf.deviation = deviation
turf.variance = variance
turf.count = count

module.exports = function(polygons, points, aggregations) {
    for (var i = 0, len = aggregations.length; i < len; i++) {
        var agg = aggregations[i],
            operation = agg.aggregation,
            unrecognizedError;

        if (isAggregationOperation(operation)) {
            if (operation === 'count') {
                polygons = turf[operation](polygons, points, agg.outField);
            } else {
                polygons = turf[operation](polygons, points, agg.inField, agg.outField);
            }
        } else {
            unrecognizedError = new Error('"' + operation + '" is not a recognized aggregation operation.');
            return err;
        }
    }

    return polygons;
}

function isAggregationOperation(operation) {
    return operation === 'average' ||
        operation === 'sum' ||
        operation === 'median' ||
        operation === 'min' ||
        operation === 'max' ||
        operation === 'deviation' ||
        operation === 'variance' ||
        operation === 'count';
}