Lucas W Lucas W - 4 months ago 64
Javascript Question

Example of using feature.forEachProperty() in Google Maps javascript v3?

Can someone provide an example of forEachProperty()?

https://developers.google.com/maps/documentation/javascript/reference#Data.Feature


forEachProperty(callback:function(*, string))


Repeatedly invokes the given function, passing a property value and
name on each invocation. The order of iteration through the properties
is undefined.


Either my google search is flawed or there is not a single instance of it being used in code samples on the web.

Answer

Consider the geoJSON in this example

It gets loaded to the data layer with

map.data.loadGeoJson('https://storage.googleapis.com/maps-devrel/google.json');

Each letter of the word Google over Australia is a Feature. Each of these features has properties and geometry. For example, if you wanted to know the letter and color properties of each feature you'd do:

map.data.forEach(function(feature) { 
    console.log(feature.get('letter'), 'is' ,feature.get('color')); 
});

And the result would be

G is blue
o is red
o is yellow
g is blue
l is green
e is red 

To get all the properties for a given feature, you would use Feature.forEachProperty()

map.data.forEach(function(feature) { 
    console.log('>> ', feature.get('letter'), 'properties are: '); 
    feature.forEachProperty(function(value,property) {
        console.log(property,':',value);
    });
});

And the result would be

>> G properties are:  
letter : G 
color : blue 
rank : 7 
ascii : 71 
>> o properties are:  
letter : o 
color : red 
rank : 15 
ascii : 111 
>> o properties are:  
letter : o 
color : yellow 
rank : 15 
ascii : 111 
>> g properties are:  
letter : g 
color : blue 
rank : 7 
ascii : 103 
>> l properties are:  
letter : l 
color : green 
rank : 12 
ascii : 108 
>> e properties are:  
letter : e 
color : red 
rank : 5 
ascii : 101