topic Re: resultOffset parameter in ArcGIS JavaScript Maps SDK Questions

resultOffset parameter

ClémentLaskar — Mon, 17 May 2021 15:14:17 GMT

I must be missing something :

The REST API supports a resultOffset parameter to fetch records that are beyond maxRecordCount. https://developers.arcgis.com/rest/services-reference/enterprise/query-feature-service-layer-.htm

However, I cannot find this parameter in the 4.19 API https://developers.arcgis.com/javascript/latest/api-reference/esri-tasks-support-OffsetParameters.html nor in the 3.36 API https://developers.arcgis.com/javascript/3/jsapi/query.html.

What is the way to get records with the 4.x version above maxRecordCount from my service ?

Thanks a lot

Re: resultOffset parameter

BlakeTerhune — Mon, 17 May 2021 15:37:44 GMT

This is what I did with 10.5.1 services. There's probably a better way now but I haven't revisited it. The undefined queryObject variable is your original query object.

// Set record limit to match the service being queried const maxRecordCount = 1000; // Ensure only one value for outFields (changed at 10.6.1) // When returnCountOnly and returnDistinctValues are true, // more than one field specified in outFields is not supported. let queryForCount = queryObject.clone(); if (queryForCount.outFields && queryForCount.outFields.length > 1) { queryForCount.outFields = [queryForCount.outFields[0]]; } let queryTask = new QueryTask({url: "urlForMyLayer"}); queryTask.executeForCount(queryForCount) .then(function(queryRecordCount) { if (queryRecordCount) { // Build array of page steps and use to query the service // as many times as necessary to retrieve all records. const pageCount = Math.ceil(queryRecordCount / maxRecordCount); let resultPages = []; for (let i = 0; i < pageCount; i++) { resultPages.push(i * maxRecordCount); } return Promise.all(resultPages.map(function(resultPageStart) { queryObject.start = resultPageStart; queryObject.num = maxRecordCount; return queryTask.execute(queryObject); })); } else { // No records to query; send back an Array with one empty FeatureSet // to mimic the return from Promise.all() console.log('No records to query'); return Promise.resolve([new FeatureSet()]); } }) .then(function(featureSets) { // Combine all features into the first FeatureSet for return. let returnFeatureSet = featureSets.pop(); featureSets.forEach(function(featureSet) { Array.prototype.push.apply(returnFeatureSet.features, featureSet.features); }); resolve(returnFeatureSet); }) .catch(function(err) { reject(err); });

Re: resultOffset parameter

JohnGrayson — Mon, 17 May 2021 15:40:04 GMT

Since you'll be using Query to retrieve the features, check out the properties available in this class; and related to your question the 'start' parameter: Query.start

Re: resultOffset parameter

ClémentLaskar — Tue, 18 May 2021 08:27:59 GMT

Thanks John ! Also it's quite confusing the parameters names are different from those in the REST API. I was indeed missing something !