AngularJS experiencing sluggish performance

Below is the loop I am using to create map markers with 1000 points:


        var markers = {};
        for (var i = 0; i < items.data.data.length; i++) {
            latVal = items.data.data[i].lat;
            lngVal = items.data.data[i].lng;
            ikona = icons.infost;
            message = "<b>" + items.data.data[i].name + "</b>";
            markers[i] = {'group': 'cmp', 'lat' : eval(latVal), 'lng' : eval(lngVal), 'icon' : ikona, 'message' : message};
        }
        $scope.Markers = markers;

Any suggestions on how to enhance the speed of this for loop in AngularJS? Currently, it takes almost 10 seconds.

javascriptangularjsloopsfor-loop

Answer №1

  1. Avoid using eval. It can slow down performance and negate browser optimizations throughout the function chain.
  2. Opt for an array like markers = [] over an object.
  3. Utilize the + operator to convert strings to numbers efficiently.
  4. Use push method when adding elements to arrays.
  5. Store results from items.data.data in a variable for better organization.

Answer №2

Improving the speed of your code involves avoiding using eval and caching loop variables and arrays. By caching certain values, unnecessary calculations and member access operations can be reduced.

var items = { data: { data: [] }};
var icons = { infost: 'infost'};
for (var i = 0; i < 1000; i++) {
  items.data.data.push({ lat: ''+i, lng: ''+i, name:''+i });
}

console.time('time');

/// YOUR CODE STARTS HERE

var
  data = items.data.data,
  l = data.length,
  markers = Array(l), // or just []
  item, latVal, lngVal, ikona, message;

for (var i = 0; i < l; i++) {
  item = data[i];

  latVal = item.lat;
  lngVal = item.lng;
  ikona = icons.infost;
  message = "<b>" + item.name + "</b>";
  markers[i] = {
    group: 'cmp',
    lat: +latVal,
    lng: +lngVal,
    icon: ikona,
    message: message
  };
}
console.timeEnd('time');
//$scope.Markers = markers;

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