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Improved documentation for feature load events.

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This commit is contained in:
Simon Seyock
2021-01-05 09:32:16 +01:00
parent 9b6114b768
commit 90c25012b9
2 changed files with 13 additions and 8 deletions
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10
src/ol/featureloader.js
View File

@@ -15,10 +15,12 @@ let withCredentials = false;
* {@link module:ol/source/Vector} sources use a function of this type to
* load features.
*
* This function takes an {@link module:ol/extent~Extent} representing the area to be loaded,
* a `{number}` representing the resolution (map units per pixel), an
* {@link module:ol/proj/Projection} for the projection and success and failure callbacks as
* arguments. `this` within the function is bound to the
* This function takes up to 5 arguments. These are an {@link module:ol/extent~Extent} representing
* the area to be loaded, a `{number}` representing the resolution (map units per pixel), an
* {@link module:ol/proj/Projection} for the projection, an optional success callback that should get
* the loaded features passed as an argument and an optional failure callback with no arguments. If
* the callbacks are not used, the corresponding vector source will not fire `'featuresloadstart'`,
* `'featuresloadend'` and `'featuresloaderror'` events. `this` within the function is bound to the
* {@link module:ol/source/Vector} it's called from.
*
* The function is responsible for loading the features and adding them to the

11
src/ol/source/Vector.js
View File

@@ -72,7 +72,8 @@ export class VectorSourceEvent extends Event {
* @property {import("../featureloader.js").FeatureLoader} [loader]
* The loader function used to load features, from a remote source for example.
* If this is not set and `url` is set, the source will create and use an XHR
* feature loader.
* feature loader. The `'featuresloadstart'`, `'featuresloadend'` and `'featuresloaderror'` events
* will only fire if the `success` and `failure` callbacks are used.
*
* Example:
*
@@ -83,7 +84,7 @@ export class VectorSourceEvent extends Event {
*
* var vectorSource = new Vector({
* format: new GeoJSON(),
* loader: function(extent, resolution, projection) {
* loader: function(extent, resolution, projection, success, failure) {
* var proj = projection.getCode();
* var url = 'https://ahocevar.com/geoserver/wfs?service=WFS&' +
* 'version=1.1.0&request=GetFeature&typename=osm:water_areas&' +
@@ -93,12 +94,14 @@ export class VectorSourceEvent extends Event {
* xhr.open('GET', url);
* var onError = function() {
* vectorSource.removeLoadedExtent(extent);
* failure();
* }
* xhr.onerror = onError;
* xhr.onload = function() {
* if (xhr.status == 200) {
* vectorSource.addFeatures(
* vectorSource.getFormat().readFeatures(xhr.responseText));
* var features = vectorSource.getFormat().readFeatures(xhr.responseText);
* vectorSource.addFeatures(features);
* success(features);
* } else {
* onError();
* }