Added supplementary function weight()

LF-2100

Author: yuriy-sedinkin

CHANGELOG.md

@@ -3,6 +3,10 @@
 This log documents significant changes for each release.  This project follows
 [Semantic Versioning](http://semver.org/).
 
+## [3.14.0] - 2024-05-09
+### Added
+- supplementary function `weight()`.
+
 ## [3.13.1] - 2024-04-24
 ### Fixed
 - an issue with evaluating an expression for a resource passed through an

package-lock.json

@@ -1,6 +1,6 @@
 {
   "name": "fhirpath",
-  "version": "3.13.1",
+  "version": "3.14.0",
   "description": "A FHIRPath engine",
   "main": "src/fhirpath.js",
   "dependencies": {

package.json

@@ -38,6 +38,7 @@ let engine    = {}; // the object with all FHIRPath functions and operations
 let existence = require("./existence");
 let filtering = require("./filtering");
 let aggregate = require("./aggregate");
+let supplements = require("./supplements");
 let combining = require("./combining");
 let misc      = require("./misc");
 let equality  = require("./equality");
@@ -83,6 +84,7 @@ engine.invocationTable = {
   min:          {fn: aggregate.minFn},
   max:          {fn: aggregate.maxFn},
   avg:          {fn: aggregate.avgFn},
+  weight:       {fn: supplements.weight},
   single:       {fn: filtering.singleFn},
   first:        {fn: filtering.firstFn},
   last:         {fn: filtering.lastFn},
@@ -194,7 +196,7 @@ engine.TermExpression = function(ctx, parentData, node) {
   if (parentData) {
     parentData = parentData.map((x) => {
       if (x instanceof Object && x.resourceType) {
-        return makeResNode(x, x.resourceType, null, x.resourceType);
+        return makeResNode(x, null, x.resourceType, null, x.resourceType);
       }
       return x;
     });
@@ -263,17 +265,17 @@ engine.ExternalConstantTerm = function(ctx, parentData, node) {
     if (Array.isArray(value)) {
       value = value.map(
         i => i?.__path__
-          ? makeResNode(i, i.__path__.path || null, null,
+          ? makeResNode(i, i.__path__.parentResNode, i.__path__.path || null, null,
             i.__path__.fhirNodeDataType || null)
           : i?.resourceType
-            ? makeResNode(i, null, null)
+            ? makeResNode(i, null, null, null)
             : i );
     } else {
       value = value?.__path__
-        ? makeResNode(value, value.__path__.path || null, null,
+        ? makeResNode(value, value.__path__.parentResNode, value.__path__.path || null, null,
           value.__path__.fhirNodeDataType || null)
         : value?.resourceType
-          ? makeResNode(value, null, null)
+          ? makeResNode(value, null, null, null)
           : value;
     }
     ctx.processedVars[varName] = value;
@@ -380,7 +382,7 @@ engine.MemberInvocation = function(ctx, parentData, node ) {
         .filter((x) => x instanceof ResourceNode && x.path === key);
     } else {
       return parentData.reduce(function(acc, res) {
-        res = makeResNode(res, res.__path__?.path || null, null,
+        res = makeResNode(res, null, res.__path__?.path || null, null,
           res.__path__?.fhirNodeDataType || null);
         util.pushFn(acc, util.makeChildResNodes(res, key, model));
         return acc;
@@ -676,14 +678,18 @@ function applyParsedPath(resource, parsedPath, context, model, options) {
   constants.reset();
   let dataRoot = util.arraify(resource).map(
     i => i?.__path__
-      ? makeResNode(i, i.__path__.path, null,
+      ? makeResNode(i, i.__path__.parentResNode, i.__path__.path, null,
         i.__path__.fhirNodeDataType || null)
       : i );
   // doEval takes a "ctx" object, and we store things in that as we parse, so we
   // need to put user-provided variable data in a sub-object, ctx.vars.
   // Set up default standard variables, and allow override from the variables.
   // However, we'll keep our own copy of dataRoot for internal processing.
-  let vars = {context: dataRoot, ucum: 'http://unitsofmeasure.org'};
+  let vars = {
+    context: dataRoot,
+    ucum: 'http://unitsofmeasure.org',
+    scoreExt: 'http://hl7.org/fhir/StructureDefinition/ordinalValue'
+  };
   let ctx = {dataRoot, processedVars: vars, vars: context || {}, model};
   if (options.traceFn) {
     ctx.customTraceFn = options.traceFn;
@@ -701,9 +707,11 @@ function applyParsedPath(resource, parsedPath, context, model, options) {
       // Path for the data extracted from the resource.
       let path;
       let fhirNodeDataType;
+      let parentResNode;
       if (n instanceof ResourceNode) {
         path = n.path;
         fhirNodeDataType = n.fhirNodeDataType;
+        parentResNode = n.parentResNode;
       }
       n = util.valData(n);
       if (n instanceof FP_Type) {
@@ -716,7 +724,7 @@ function applyParsedPath(resource, parsedPath, context, model, options) {
         // Add a hidden (non-enumerable) property with the path to the data extracted
         // from the resource.
         if (path && typeof n === 'object' && !n.__path__) {
-          Object.defineProperty(n, '__path__', { value: {path, fhirNodeDataType} });
+          Object.defineProperty(n, '__path__', { value: {path, fhirNodeDataType, parentResNode} });
         }
         acc.push(n);
       }
@@ -828,7 +836,7 @@ function compile(path, model, options) {
         const baseFhirNodeDataType = model && model.path2Type[basePath] || null;
         basePath = baseFhirNodeDataType === 'BackboneElement' || baseFhirNodeDataType === 'Element' ? basePath : baseFhirNodeDataType || basePath;
 
-        fhirData = makeResNode(fhirData, basePath, null, baseFhirNodeDataType);
+        fhirData = makeResNode(fhirData, null, basePath, null, baseFhirNodeDataType);
       }
       // Globally set model before applying parsed FHIRPath expression
       TypeInfo.model = model;
@@ -854,8 +862,8 @@ function typesFn(fhirpathResult) {
   return util.arraify(fhirpathResult).map(value => {
     const ti = TypeInfo.fromValue(
       value?.__path__
-        ? new ResourceNode(value, value.__path__?.path, null,
-          value.__path__?.fhirNodeDataType)
+        ? new ResourceNode(value, value.__path__?.parentResNode || null,
+          value.__path__?.path || null, null, value.__path__?.fhirNodeDataType || null)
         : value );
     return `${ti.namespace}.${ti.name}`;
   });

src/fhirpath.js

@@ -28,7 +28,7 @@ engine.extension = function(parentData, url) {
     if (extensions) {
       return extensions
         .filter(extension => extension.url === url)
-        .map(x => ResourceNode.makeResNode(x, 'Extension', null, 'Extension'));
+        .map(e => ResourceNode.makeResNode(e, x, 'Extension', null, 'Extension'));
     }
     return [];
   }));
@@ -67,9 +67,9 @@ engine.repeatMacro = function(parentData, expr) {
 
 //TODO: behavior on object?
 engine.singleFn = function(x) {
-  if(x.length == 1){
+  if(x.length === 1){
     return x;
-  } else if (x.length == 0) {
+  } else if (x.length === 0) {
     return [];
   } else {
     throw new Error("Expected single");

src/filtering.js

@@ -0,0 +1,78 @@
+// Contains the supplementary FHIRPath functions.
+
+let engine = {};
+
+/**
+ * Returns numeric values from the score extension associated with the input
+ * collection of Questionnaire items. See the description of the ordinal()
+ * function here:
+ * https://hl7.org/fhir/uv/sdc/expressions.html#fhirpath-supplements
+ * @param {Array} coll - questionnaire items
+ * @return {number[]}
+ */
+engine.weight = function (coll) {
+  if(coll !== false && ! coll) { return []; }
+
+  const scoreExtUrl = this.vars.scoreExt || this.processedVars.scoreExt;
+  const res = [];
+  const linkId2Code = {};
+
+  coll.forEach((answer) => {
+    if (answer.data.valueCoding) {
+      const score = answer.data.extension?.find(e => e.url === scoreExtUrl)?.valueDecimal;
+      if (score !== undefined) {
+        // if we have a score extension in the source item, use it.
+        res.push(score);
+      } else {
+        // otherwise we will try to find the score in the %questionnaire.
+        linkId2Code[answer.parentResNode.data.linkId] = answer.data.valueCoding.code;
+      }
+    }
+  });
+
+  const questionnaire = this.vars.questionnaire || this.processedVars.questionnaire?.data;
+  if (questionnaire) {
+    forEachQItem(questionnaire, (qItem) => {
+      const code = linkId2Code[qItem.linkId];
+      if (code) {
+        const answerOption = qItem.answerOption?.find(o => o.valueCoding.code === code);
+        if (answerOption) {
+          delete linkId2Code[qItem.linkId];
+          const score = answerOption.extension?.find(e => e.url === scoreExtUrl)?.valueDecimal;
+          if (score !== undefined) {
+            // if we have a score extension for the answerOption, use it.
+            res.push(score);
+          }
+        }
+      }
+    });
+  }
+
+  // Check for errors.
+  const unfoundLinkIds = Object.keys(linkId2Code);
+  if (unfoundLinkIds.length) {
+    if (questionnaire) {
+      throw new Error('Questionnaire answerOptions with these linkIds were not found: ' + unfoundLinkIds.join(',') + '.');
+    } else {
+      throw new Error('%questionnaire is needed but not specified.');
+    }
+  }
+
+  return res;
+};
+
+/**
+ * Runs a function for each questionnaire item.
+ * @param {Object} questionnaire - Questionnaire resource.
+ * @param {(item) => void} fn - function.
+ */
+function forEachQItem(questionnaire, fn) {
+  if(questionnaire.item) {
+    questionnaire.item.forEach((item) => {
+      fn(item);
+      forEachQItem(item, fn);
+    });
+  }
+}
+
+module.exports = engine;

src/supplements.js

@@ -1287,23 +1287,25 @@ class ResourceNode {
    *  Constructs a instance for the given node ("data") of a resource.  If the
    *  data is the top-level node of a resouce, the path and type parameters will
    *  be ignored in favor of the resource's resourceType field.
-   * @param {*} data the node's data or value (which might be an object with
+   * @param {*} data - the node's data or value (which might be an object with
    *  sub-nodes, an array, or FHIR data type)
-   * @param {string} path the node's path in the resource (e.g. Patient.name).
+   * @param {ResourceNode} parentResNode - parent ResourceNode.
+   * @param {string} path - the node's path in the resource (e.g. Patient.name).
    *  If the data's type can be determined from data, that will take precedence
    *  over this parameter.
-   * @param {*} _data additional data stored in a property named with "_"
+   * @param {*} _data - additional data stored in a property named with "_"
    *  prepended, see https://www.hl7.org/fhir/element.html#json for details.
-   * @param {string} fhirNodeDataType FHIR node data type, if the resource node
+   * @param {string} fhirNodeDataType - FHIR node data type, if the resource node
    *  is described in the FHIR model.
    */
-  constructor(data, path, _data, fhirNodeDataType) {
+  constructor(data, parentResNode, path, _data, fhirNodeDataType) {
     // If data is a resource (maybe a contained resource) reset the path
     // information to the resource type.
     if (data?.resourceType) {
       path = data.resourceType;
       fhirNodeDataType = data.resourceType;
     }
+    this.parentResNode = parentResNode;
     this.path = path;
     this.data = data;
     this._data = _data || {};
@@ -1384,8 +1386,8 @@ class ResourceNode {
  *  given node is already a ResourceNode.  Takes the same arguments as the
  *  constructor for ResourceNode.
  */
-ResourceNode.makeResNode = function(data, path, _data, fhirNodeDataType = null) {
-  return (data instanceof ResourceNode) ? data : new ResourceNode(data, path, _data, fhirNodeDataType);
+ResourceNode.makeResNode = function(data, parentResNode, path, _data, fhirNodeDataType = null) {
+  return (data instanceof ResourceNode) ? data : new ResourceNode(data, parentResNode, path, _data, fhirNodeDataType);
 };
 
 // The set of available data types in the System namespace

src/types.js

@@ -47,7 +47,7 @@ util.assertType = function(data, types, errorMsgPrefix) {
 };
 
 util.isEmpty = function(x){
-  return Array.isArray(x) && x.length == 0;
+  return Array.isArray(x) && x.length === 0;
 };
 
 util.isSome = function(x){
@@ -56,7 +56,7 @@ util.isSome = function(x){
 
 util.isTrue = function(x){
   // We use util.valData because we can use a boolean node as a criterion
-  return x !== null && x !== undefined && (x === true || (x.length == 1 && util.valData(x[0]) === true));
+  return x !== null && x !== undefined && (x === true || (x.length === 1 && util.valData(x[0]) === true));
 };
 
 util.isCapitalized = function(x){
@@ -172,20 +172,20 @@ util.makeChildResNodes = function(parentResNode, childProperty, model) {
   if (util.isSome(toAdd) || util.isSome(_toAdd)) {
     if(Array.isArray(toAdd)) {
       result = toAdd.map((x, i)=>
-        ResourceNode.makeResNode(x, childPath, _toAdd && _toAdd[i], fhirNodeDataType));
+        ResourceNode.makeResNode(x, parentResNode, childPath, _toAdd && _toAdd[i], fhirNodeDataType));
       // Add items to the end of the ResourceNode list that have no value
       // but have associated data, such as extensions or ids.
       const _toAddLength = _toAdd?.length || 0;
       for (let i = toAdd.length; i < _toAddLength; ++i) {
-        result.push(ResourceNode.makeResNode(null, childPath, _toAdd[i], fhirNodeDataType));
+        result.push(ResourceNode.makeResNode(null, parentResNode, childPath, _toAdd[i], fhirNodeDataType));
       }
     } else if (toAdd == null && Array.isArray(_toAdd)) {
       // Add items to the end of the ResourceNode list when there are no
       // values at all, but there is a list of associated data, such as
       // extensions or ids.
-      result = _toAdd.map((x) => ResourceNode.makeResNode(null, childPath, x, fhirNodeDataType));
+      result = _toAdd.map((x) => ResourceNode.makeResNode(null, parentResNode, childPath, x, fhirNodeDataType));
     } else {
-      result = [ResourceNode.makeResNode(toAdd, childPath, _toAdd, fhirNodeDataType)];
+      result = [ResourceNode.makeResNode(toAdd, parentResNode, childPath, _toAdd, fhirNodeDataType)];
     }
   } else {
     result = [];