Edit

Example of making a WFS GetFeature request with a filter.

This example generates a GetFeature request which uses a PropertyIsEqualTo and a PropertyIsLike filter, and then posts the request to load the features that match the query.

main.js
import Map from 'ol/Map.js';
import VectorSource from 'ol/source/Vector.js';
import View from 'ol/View.js';
import XYZ from 'ol/source/XYZ.js';
import {GeoJSON, WFS} from 'ol/format.js';
import {Stroke, Style} from 'ol/style.js';
import {Tile as TileLayer, Vector as VectorLayer} from 'ol/layer.js';
import {
  and as andFilter,
  equalTo as equalToFilter,
  like as likeFilter,
} from 'ol/format/filter.js';

const vectorSource = new VectorSource();
const vector = new VectorLayer({
  source: vectorSource,
  style: new Style({
    stroke: new Stroke({
      color: 'rgba(0, 0, 255, 1.0)',
      width: 2,
    }),
  }),
});

const key = 'Get your own API key at https://www.maptiler.com/cloud/';
const attributions =
  '<a href="https://www.maptiler.com/copyright/" target="_blank">&copy; MapTiler</a> ' +
  '<a href="https://www.openstreetmap.org/copyright" target="_blank">&copy; OpenStreetMap contributors</a>';

const raster = new TileLayer({
  source: new XYZ({
    attributions: attributions,
    url: 'https://api.maptiler.com/tiles/satellite/{z}/{x}/{y}.jpg?key=' + key,
    maxZoom: 20,
  }),
});

const map = new Map({
  layers: [raster, vector],
  target: document.getElementById('map'),
  view: new View({
    center: [-8908887.277395891, 5381918.072437216],
    maxZoom: 19,
    zoom: 12,
  }),
});

// generate a GetFeature request
const featureRequest = new WFS().writeGetFeature({
  srsName: 'EPSG:3857',
  featureNS: 'http://openstreemap.org',
  featurePrefix: 'osm',
  featureTypes: ['water_areas'],
  outputFormat: 'application/json',
  filter: andFilter(
    likeFilter('name', 'Mississippi*'),
    equalToFilter('waterway', 'riverbank'),
  ),
});

// then post the request and add the received features to a layer
fetch('https://ahocevar.com/geoserver/wfs', {
  method: 'POST',
  body: new XMLSerializer().serializeToString(featureRequest),
})
  .then(function (response) {
    return response.json();
  })
  .then(function (json) {
    const features = new GeoJSON().readFeatures(json);
    vectorSource.addFeatures(features);
    map.getView().fit(vectorSource.getExtent());
  });
index.html
<!DOCTYPE html>
<html lang="en">
  <head>
    <meta charset="UTF-8">
    <title>WFS - GetFeature</title>
    <link rel="stylesheet" href="node_modules/ol/ol.css">
    <style>
      .map {
        width: 100%;
        height: 400px;
      }
    </style>
  </head>
  <body>
    <div id="map" class="map"></div>

    <script type="module" src="main.js"></script>
  </body>
</html>
package.json
{
  "name": "vector-wfs-getfeature",
  "dependencies": {
    "ol": "9.1.0"
  },
  "devDependencies": {
    "vite": "^3.2.3"
  },
  "scripts": {
    "start": "vite",
    "build": "vite build"
  }
}