For Each loop ---> For loop

Question

I am having a error that states that data.forEach is not a function. The code is:

function getProperGeojsonFormat(data) {
    isoGeojson = {"type": "FeatureCollection", "features": []};

    console.log("After getProperGeojsonFormat function")
    console.log(data)
    console.log("")

    data.forEach(function(element, index) {
        isoGeojson.features[index] = {};
        isoGeojson.features[index].type = 'Feature';
        isoGeojson.features[index].properties = element.properties;
        isoGeojson.features[index].geometry = {};
        isoGeojson.features[index].geometry.coordinates = [];
        isoGeojson.features[index].geometry.type = 'MultiPolygon';

        element.geometry.geometries.forEach(function(el) {
            isoGeojson.features[index].geometry.coordinates.push(el.coordinates);
        });
    });
    $rootScope.$broadcast('isochrones', {isoGeom: isoGeojson});



}

The error I am getting is:

When I console log data:

JSON in JS is a string. Strings in JS do not have a `forEach` method. — zerkms, Jun 23 '16 at 01:48
I think OP means that his data is an object (classic confusion between JSON and objects). — Quentin Roy, Jun 23 '16 at 01:48
JSON can represent an object or an array. It appears that this JSON represents an object. — Ray Nicholus, Jun 23 '16 at 01:49
To tell if something is an array, look at http://stackoverflow.com/questions/4775722/check-if-object-is-array. That link also shows you how to turn a single object *into* an array containing that object, if that's what you want. — paxdiablo, Jun 23 '16 at 01:49
@Mr.KGK no you don't. Using `for` over strings also makes very little sense. — zerkms, Jun 23 '16 at 01:49
You have `console.log(data)` -- can't you tell by looking at it whether it's an array or not? If it's an array it will have `[]` around it. — Barmar, Jun 23 '16 at 02:17

Quentin Roy · Answer 1 · 2016-06-23T02:13:46.010

forEach works on arrays, not on objects. It seems here that data is an object.

Use this instead.

Object.keys(data).forEach(function(index) {
    var element = data[index];
    isoGeojson.features[index] = {};
    isoGeojson.features[index].type = 'Feature';
    isoGeojson.features[index].properties = element.properties;
    isoGeojson.features[index].geometry = {};
    isoGeojson.features[index].geometry.coordinates = [];
    isoGeojson.features[index].geometry.type = 'MultiPolygon';

    element.geometry.geometries.forEach(function(el) {
        isoGeojson.features[index].geometry.coordinates.push(el.coordinates);
    });
});

Object.keys creates an array from the keys of an object. You can then iterate over these keys and fetch the associated value. This approach will work on any objects.

score 0 · Accepted Answer · answered Jun 23 '16 at 02:35

0

data is an object. It looks like you want to loop over the features array within that object, so do:

data.features.forEach(function(element, index) {
    isoGeojson.features[index] = {
        type: 'Feature',
        properties: element.properties,
        geometry: {
            type: 'MultiPolygon',
            coordinates: element.coordinates.slice()
        }            
    }
});

answered Jun 23 '16 at 02:35

Barmar

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Thanks for the hint to change data.features.forEach. Now i have a issue with the next forEach – Mr.KGK Jun 23 '16 at 02:53
Apologies, but it back there – Mr.KGK Jun 23 '16 at 02:59
Stop putting the answer into the question. I've put back the original question. – Barmar Jun 23 '16 at 13:51

For Each loop ---> For loop

2 Answers2