Distance between repeatable points

/*! geolib 2.0.21 by Manuel Bieh
* Library to provide geo functions like distance calculation,
* conversion of decimal coordinates to sexagesimal and vice versa, etc.
* WGS 84 (World Geodetic System 1984)
*
* @author Manuel Bieh
* @url http://www.manuelbieh.com/
* @version 2.0.21
* @license MIT
**/
!function(t){if("object"==typeof exports&&"undefined"!=typeof module)module.exports=t();else if("function"==typeof define&&define.amd)define([],t);else{var e;e="undefined"!=typeof window?window:"undefined"!=typeof global?global:"undefined"!=typeof self?self:this,e.geolib=t()}}(function(){var t;return function t(e,i,a){function n(s,r){if(!i[s]){if(!e[s]){var u="function"==typeof require&&require;if(!r&&u)return u(s,!0);if(o)return o(s,!0);var h=new Error("Cannot find module '"+s+"'");throw h.code="MODULE_NOT_FOUND",h}var l=i[s]={exports:{}};e[s][0].call(l.exports,function(t){var i=e[s][1][t];return n(i?i:t)},l,l.exports,t,e,i,a)}return i[s].exports}for(var o="function"==typeof require&&require,s=0;s<a.length;s++)n(a[s]);return n}({geolib:[function(e,i,a){!function(e,a){"use strict";function n(){}n.TO_RAD=Math.PI/180,n.TO_DEG=180/Math.PI,n.PI_X2=2*Math.PI,n.PI_DIV4=Math.PI/4;var o=Object.create(n.prototype,{version:{value:"2.0.21"},radius:{value:6378137},minLat:{value:-90},maxLat:{value:90},minLon:{value:-180},maxLon:{value:180},sexagesimalPattern:{value:/^([0-9]{1,3})°\s*([0-9]{1,3}(?:\.(?:[0-9]{1,2}))?)'\s*(([0-9]{1,3}(\.([0-9]{1,4}))?)"\s*)?([NEOSW]?)$/},measures:{value:Object.create(Object.prototype,{m:{value:1},km:{value:.001},cm:{value:100},mm:{value:1e3},mi:{value:1/1609.344},sm:{value:1/1852.216},ft:{value:100/30.48},in:{value:100/2.54},yd:{value:1/.9144}})},prototype:{value:n.prototype},extend:{value:function(t,e){for(var i in t)"undefined"!=typeof o.prototype[i]&&e!==!0||("function"==typeof t[i]&&"function"==typeof t[i].bind?o.prototype[i]=t[i].bind(o):o.prototype[i]=t[i])}}});"undefined"==typeof Number.prototype.toRad&&(Number.prototype.toRad=function(){return this*n.TO_RAD}),"undefined"==typeof Number.prototype.toDeg&&(Number.prototype.toDeg=function(){return this*n.TO_DEG}),o.extend({decimal:{},sexagesimal:{},distance:null,getKeys:function(t){if("[object Array]"==Object.prototype.toString.call(t))return{longitude:t.length>=1?0:a,latitude:t.length>=2?1:a,elevation:t.length>=3?2:a};var e=function(e){var i;return e.every(function(e){return"object"!=typeof t||(!t.hasOwnProperty(e)||function(){return i=e,!1}())}),i},i=e(["lng","lon","longitude"]),n=e(["lat","latitude"]),o=e(["alt","altitude","elevation","elev"]);return"undefined"==typeof n&&"undefined"==typeof i&&"undefined"==typeof o?a:{latitude:n,longitude:i,elevation:o}},getLat:function(t,e){return e===!0?t[this.getKeys(t).latitude]:this.useDecimal(t[this.getKeys(t).latitude])},latitude:function(t){return this.getLat.call(this,t)},getLon:function(t,e){return e===!0?t[this.getKeys(t).longitude]:this.useDecimal(t[this.getKeys(t).longitude])},longitude:function(t){return this.getLon.call(this,t)},getElev:function(t){return t[this.getKeys(t).elevation]},elevation:function(t){return this.getElev.call(this,t)},coords:function(t,e){var i={latitude:e===!0?t[this.getKeys(t).latitude]:this.useDecimal(t[this.getKeys(t).latitude]),longitude:e===!0?t[this.getKeys(t).longitude]:this.useDecimal(t[this.getKeys(t).longitude])},a=t[this.getKeys(t).elevation];return"undefined"!=typeof a&&(i.elevation=a),i},ll:function(t,e){return this.coords.call(this,t,e)},validate:function(t){var e=this.getKeys(t);if("undefined"==typeof e||"undefined"==typeof e.latitude||"undefined"===e.longitude)return!1;var i=t[e.latitude],a=t[e.longitude];return!("undefined"==typeof i||!this.isDecimal(i)&&!this.isSexagesimal(i))&&(!("undefined"==typeof a||!this.isDecimal(a)&&!this.isSexagesimal(a))&&(i=this.useDecimal(i),a=this.useDecimal(a),!(i<this.minLat||i>this.maxLat||a<this.minLon||a>this.maxLon)))},getDistance:function(t,e,i,a){i=Math.floor(i)||1,a=Math.floor(a)||0;var n,s,r,u,h,l,d,c=this.coords(t),g=this.coords(e),f=6378137,m=6356752.314245,p=1/298.257223563,v=(g.longitude-c.longitude).toRad(),M=Math.atan((1-p)*Math.tan(parseFloat(c.latitude).toRad())),y=Math.atan((1-p)*Math.tan(parseFloat(g.latitude).toRad())),x=Math.sin(M),D=Math.cos(M),b=Math.sin(y),L=Math.cos(y),R=v,P=100;do{var N=Math.sin(R),E=Math.cos(R);if(l=Math.sqrt(L*N*(L*N)+(D*b-x*L*E)*(D*b-x*L*E)),0===l)return o.distance=0;n=x*b+D*L*E,s=Math.atan2(l,n),r=D*L*N/l,u=1-r*r,h=n-2*x*b/u,isNaN(h)&&(h=0);var I=p/16*u*(4+p*(4-3*u));d=R,R=v+(1-I)*p*r*(s+I*l*(h+I*n*(-1+2*h*h)))}while(Math.abs(R-d)>1e-12&&--P>0);if(0===P)return NaN;var S=u*(f*f-m*m)/(m*m),F=1+S/16384*(4096+S*(-768+S*(320-175*S))),w=S/1024*(256+S*(-128+S*(74-47*S))),k=w*l*(h+w/4*(n*(-1+2*h*h)-w/6*h*(-3+4*l*l)*(-3+4*h*h))),O=m*F*(s-k);if(O=O.toFixed(a),"undefined"!=typeof this.elevation(t)&&"undefined"!=typeof this.elevation(e)){var W=Math.abs(this.elevation(t)-this.elevation(e));O=Math.sqrt(O*O+W*W)}return this.distance=Math.round(O*Math.pow(10,a)/i)*i/Math.pow(10,a)},getDistanceSimple:function(t,e,i){i=Math.floor(i)||1;var a=Math.round(Math.acos(Math.sin(this.latitude(e).toRad())*Math.sin(this.latitude(t).toRad())+Math.cos(this.latitude(e).toRad())*Math.cos(this.latitude(t).toRad())*Math.cos(this.longitude(t).toRad()-this.longitude(e).toRad()))*this.radius);return o.distance=Math.floor(Math.round(a/i)*i)},getCenter:function(t){var e=t;if("object"==typeof t&&!(t instanceof Array)){e=[];for(var i in t)e.push(this.coords(t[i]))}if(!e.length)return!1;var a,o,s,r=0,u=0,h=0;e.forEach(function(t){a=this.latitude(t).toRad(),o=this.longitude(t).toRad(),r+=Math.cos(a)*Math.cos(o),u+=Math.cos(a)*Math.sin(o),h+=Math.sin(a)},this);var l=e.length;return r/=l,u/=l,h/=l,o=Math.atan2(u,r),s=Math.sqrt(r*r+u*u),a=Math.atan2(h,s),{latitude:(a*n.TO_DEG).toFixed(6),longitude:(o*n.TO_DEG).toFixed(6)}},getBounds:function(t){if(!t.length)return!1;var e=this.elevation(t[0]),i={maxLat:-(1/0),minLat:1/0,maxLng:-(1/0),minLng:1/0};"undefined"!=typeof e&&(i.maxElev=0,i.minElev=1/0);for(var a=0,n=t.length;a<n;++a)i.maxLat=Math.max(this.latitude(t[a]),i.maxLat),i.minLat=Math.min(this.latitude(t[a]),i.minLat),i.maxLng=Math.max(this.longitude(t[a]),i.maxLng),i.minLng=Math.min(this.longitude(t[a]),i.minLng),e&&(i.maxElev=Math.max(this.elevation(t[a]),i.maxElev),i.minElev=Math.min(this.elevation(t[a]),i.minElev));return i},getCenterOfBounds:function(t){var e=this.getBounds(t),i=e.minLat+(e.maxLat-e.minLat)/2,a=e.minLng+(e.maxLng-e.minLng)/2;return{latitude:parseFloat(i.toFixed(6)),longitude:parseFloat(a.toFixed(6))}},getBoundsOfDistance:function(t,e){var i,a,o=this.latitude(t),s=this.longitude(t),r=o.toRad(),u=s.toRad(),h=e/this.radius,l=r-h,d=r+h,c=this.maxLat.toRad(),g=this.minLat.toRad(),f=this.maxLon.toRad(),m=this.minLon.toRad();if(l>g&&d<c){var p=Math.asin(Math.sin(h)/Math.cos(r));i=u-p,i<m&&(i+=n.PI_X2),a=u+p,a>f&&(a-=n.PI_X2)}else l=Math.max(l,g),d=Math.min(d,c),i=m,a=f;return[{latitude:l.toDeg(),longitude:i.toDeg()},{latitude:d.toDeg(),longitude:a.toDeg()}]},isPointInside:function(t,e){for(var i=!1,a=-1,n=e.length,o=n-1;++a<n;o=a)(this.longitude(e[a])<=this.longitude(t)&&this.longitude(t)<this.longitude(e[o])||this.longitude(e[o])<=this.longitude(t)&&this.longitude(t)<this.longitude(e[a]))&&this.latitude(t)<(this.latitude(e[o])-this.latitude(e[a]))*(this.longitude(t)-this.longitude(e[a]))/(this.longitude(e[o])-this.longitude(e[a]))+this.latitude(e[a])&&(i=!i);return i},preparePolygonForIsPointInsideOptimized:function(t){for(var e=0,i=t.length-1;e<t.length;e++)this.longitude(t[i])===this.longitude(t[e])?(t[e].constant=this.latitude(t[e]),t[e].multiple=0):(t[e].constant=this.latitude(t[e])-this.longitude(t[e])*this.latitude(t[i])/(this.longitude(t[i])-this.longitude(t[e]))+this.longitude(t[e])*this.latitude(t[e])/(this.longitude(t[i])-this.longitude(t[e])),t[e].multiple=(this.latitude(t[i])-this.latitude(t[e]))/(this.longitude(t[i])-this.longitude(t[e]))),i=e},isPointInsideWithPreparedPolygon:function(t,e){for(var i=!1,a=this.longitude(t),n=this.latitude(t),o=0,s=e.length-1;o<e.length;o++)(this.longitude(e[o])<a&&this.longitude(e[s])>=a||this.longitude(e[s])<a&&this.longitude(e[o])>=a)&&(i^=a*e[o].multiple+e[o].constant<n),s=o;return i},isInside:function(){return this.isPointInside.apply(this,arguments)},isPointInCircle:function(t,e,i){return this.getDistance(t,e)<i},withinRadius:function(){return this.isPointInCircle.apply(this,arguments)},getRhumbLineBearing:function(t,e){var i=this.longitude(e).toRad()-this.longitude(t).toRad(),a=Math.log(Math.tan(this.latitude(e).toRad()/2+n.PI_DIV4)/Math.tan(this.latitude(t).toRad()/2+n.PI_DIV4));return Math.abs(i)>Math.PI&&(i=i>0?(n.PI_X2-i)*-1:n.PI_X2+i),(Math.atan2(i,a).toDeg()+360)%360},getBearing:function(t,e){e.latitude=this.latitude(e),e.longitude=this.longitude(e),t.latitude=this.latitude(t),t.longitude=this.longitude(t);var i=(Math.atan2(Math.sin(e.longitude.toRad()-t.longitude.toRad())*Math.cos(e.latitude.toRad()),Math.cos(t.latitude.toRad())*Math.sin(e.latitude.toRad())-Math.sin(t.latitude.toRad())*Math.cos(e.latitude.toRad())*Math.cos(e.longitude.toRad()-t.longitude.toRad())).toDeg()+360)%360;return i},getCompassDirection:function(t,e,i){var a,n;switch(n="circle"==i?this.getBearing(t,e):this.getRhumbLineBearing(t,e),Math.round(n/22.5)){case 1:a={exact:"NNE",rough:"N"};break;case 2:a={exact:"NE",rough:"N"};break;case 3:a={exact:"ENE",rough:"E"};break;case 4:a={exact:"E",rough:"E"};break;case 5:a={exact:"ESE",rough:"E"};break;case 6:a={exact:"SE",rough:"E"};break;case 7:a={exact:"SSE",rough:"S"};break;case 8:a={exact:"S",rough:"S"};break;case 9:a={exact:"SSW",rough:"S"};break;case 10:a={exact:"SW",rough:"S"};break;case 11:a={exact:"WSW",rough:"W"};break;case 12:a={exact:"W",rough:"W"};break;case 13:a={exact:"WNW",rough:"W"};break;case 14:a={exact:"NW",rough:"W"};break;case 15:a={exact:"NNW",rough:"N"};break;default:a={exact:"N",rough:"N"}}return a.bearing=n,a},getDirection:function(t,e,i){return this.getCompassDirection.apply(this,arguments)},orderByDistance:function(t,e){var i=[];for(var a in e){var n=this.getDistance(t,e[a]),o=Object.create(e[a]);o.distance=n,o.key=a,i.push(o)}return i.sort(function(t,e){return t.distance-e.distance})},isPointInLine:function(t,e,i){return(this.getDistance(e,t,1,3)+this.getDistance(t,i,1,3)).toFixed(3)==this.getDistance(e,i,1,3)},isPointNearLine:function(t,e,i,a){return this.getDistanceFromLine(t,e,i)<a},getDistanceFromLine:function(t,e,i){var a=this.getDistance(e,t,1,3),n=this.getDistance(t,i,1,3),o=this.getDistance(e,i,1,3),s=0,r=Math.acos((a*a+o*o-n*n)/(2*a*o)),u=Math.acos((n*n+o*o-a*a)/(2*n*o));return s=r>Math.PI/2?a:u>Math.PI/2?n:Math.sin(r)*a},findNearest:function(t,e,i,a){i=i||0,a=a||1;var n=this.orderByDistance(t,e);return 1===a?n[i]:n.splice(i,a)},getPathLength:function(t){for(var e,i=0,a=0,n=t.length;a<n;++a)e&&(i+=this.getDistance(this.coords(t[a]),e)),e=this.coords(t[a]);return i},getSpeed:function(t,e,i){var a=i&&i.unit||"km";"mph"==a?a="mi":"kmh"==a&&(a="km");var n=o.getDistance(t,e),s=1*e.time/1e3-1*t.time/1e3,r=n/s*3600,u=Math.round(r*this.measures[a]*1e4)/1e4;return u},computeDestinationPoint:function(t,e,i,a){var n=this.latitude(t),o=this.longitude(t);a="undefined"==typeof a?this.radius:Number(a);var s=Number(e)/a,r=Number(i).toRad(),u=Number(n).toRad(),h=Number(o).toRad(),l=Math.asin(Math.sin(u)*Math.cos(s)+Math.cos(u)*Math.sin(s)*Math.cos(r)),d=h+Math.atan2(Math.sin(r)*Math.sin(s)*Math.cos(u),Math.cos(s)-Math.sin(u)*Math.sin(l));return d=(d+3*Math.PI)%(2*Math.PI)-Math.PI,{latitude:l.toDeg(),longitude:d.toDeg()}},convertUnit:function(t,e,i){if(0===e)return 0;if("undefined"==typeof e){if(null===this.distance)throw new Error("No distance was given");if(0===this.distance)return 0;e=this.distance}if(t=t||"m",i=null==i?4:i,"undefined"!=typeof this.measures[t])return this.round(e*this.measures[t],i);throw new Error("Unknown unit for conversion.")},useDecimal:function(t){if("[object Array]"===Object.prototype.toString.call(t)){var e=this;return t=t.map(function(t){if(e.isDecimal(t))return e.useDecimal(t);if("object"==typeof t){if(e.validate(t))return e.coords(t);for(var i in t)t[i]=e.useDecimal(t[i]);return t}return e.isSexagesimal(t)?e.sexagesimal2decimal(t):t})}if("object"==typeof t&&this.validate(t))return this.coords(t);if("object"==typeof t){for(var i in t)t[i]=this.useDecimal(t[i]);return t}if(this.isDecimal(t))return parseFloat(t);if(this.isSexagesimal(t)===!0)return parseFloat(this.sexagesimal2decimal(t));throw new Error("Unknown format.")},decimal2sexagesimal:function(t){if(t in this.sexagesimal)return this.sexagesimal[t];var e=t.toString().split("."),i=Math.abs(e[0]),a=60*("0."+(e[1]||0)),n=a.toString().split(".");return a=Math.floor(a),n=(60*("0."+(n[1]||0))).toFixed(2),this.sexagesimal[t]=i+"° "+a+"' "+n+'"',this.sexagesimal[t]},sexagesimal2decimal:function(t){if(t in this.decimal)return this.decimal[t];var e=new RegExp(this.sexagesimalPattern),i=e.exec(t),a=0,n=0;i&&(a=parseFloat(i[2]/60),n=parseFloat(i[4]/3600)||0);var o=(parseFloat(i[1])+a+n).toFixed(8);return o="S"==i[7]||"W"==i[7]?parseFloat(-o):parseFloat(o),this.decimal[t]=o,o},isDecimal:function(t){return t=t.toString().replace(/\s*/,""),!isNaN(parseFloat(t))&&parseFloat(t)==t},isSexagesimal:function(t){return t=t.toString().replace(/\s*/,""),this.sexagesimalPattern.test(t)},round:function(t,e){var i=Math.pow(10,e);return Math.round(t*i)/i}}),"undefined"!=typeof i&&"undefined"!=typeof i.exports?(i.exports=o,"object"==typeof e&&(e.geolib=o)):"function"==typeof t&&t.amd?t("geolib",[],function(){return o}):e.geolib=o}(this)},{}]},{},[])("geolib")});
// end of Geolib code

// set geolib library as a variable
var geolib = module.exports;

// empty array to hold coordinate objects
var pathCoordinates = [];

// if there is more than 1 item in the repeatable field named "sites", loop through the repeatable objects and push the coordinates into the pathCoordinates array
if ($sites && $sites.length > 1) {
  for (var i = 0; i < $sites.length; ++i) {
    pathCoordinates.push({
      latitude: $sites[i].geometry.coordinates[1],
      longitude: $sites[i].geometry.coordinates[0]
    });
  }

  // get the distance between points in meters
  var distance = geolib.getPathLength(pathCoordinates);

  // set the result of the calc field with a label
  SETRESULT(distance + " meters");
} else {
  SETRESULT(null);
}