Merge pull request #36 in LFOR/fhirpath.js from feature/LF-2171/inter…

…sect to master

* commit '1a24c742108781275e6721696ce5738713ffa60d':
  Updated CHANGELOG.md
  Minor fixes
  Fixed issues found during review
  union(), distinct() and intersect() should not depend on the order of properties in an object
  Support intersect()

CHANGELOG.md

@@ -3,6 +3,15 @@
 This log documents significant changes for each release. This project follows
 [Semantic Versioning](http://semver.org/).
 
+## [2.14.0] - 2022-03-02
+### Added
+- Function to get the intersection of two collections: intersect().
+### Fixed
+- The distinct, union, subsetOf, and intersect functions now use
+ the "6.1.1. = (Equals)" function to compare collection items instead of using
+ a map with JSON keys, which can affect their performance because the
+ complexity of the algorithm has changed from O(n) to O(n**2).
+
 ## [2.13.0] - 2022-02-28
 ### Added
 - Current time function: timeOfDay().

package.json

@@ -1,6 +1,6 @@
 {
  "name": "fhirpath",
- "version": "2.13.0",
+ "version": "2.14.0",
  "description": "A FHIRPath engine",
  "main": "src/fhirpath.js",
  "dependencies": {

src/combining.js

@@ -1,7 +1,8 @@
 // This file holds code to hande the FHIRPath Combining functions.
 
-var combineFns = {};
-var existence = require('./existence');
+const combineFns = {};
+const existence = require('./existence');
+const deepEqual = require('./deep-equal');
 
 combineFns.union = function(coll1, coll2){
  return existence.distinctFn(coll1.concat(coll2));
@@ -11,5 +12,16 @@ combineFns.combineFn = function(coll1, coll2){
  return coll1.concat(coll2);
 };
 
+combineFns.intersect = function(coll1, coll2) {
+ let result = [];
+ if (coll1.length && coll2.length) {
+ result = existence.distinctFn(coll1).filter(
+ obj1 => coll2.some(obj2 => deepEqual(obj1, obj2))
+ );
+ }
+
+ return result;
+};
+
 
 module.exports = combineFns;

src/deep-equal.js

@@ -54,12 +54,8 @@ var deepEqual = function (actual, expected, opts) {
 
  if (actual instanceof Date && expected instanceof Date) {
  return actual.getTime() === expected.getTime();
-
- // 7.3. Other pairs that do not both pass typeof value == 'object',
- // equivalence is determined by ==.
  } else if (!actual || !expected || typeof actual != 'object' && typeof expected != 'object') {
- return opts.strict ? actual === expected : actual == expected;
-
+ return actual === expected;
  }
  else {
  var actualIsFPT = actual instanceof FP_Type;

src/existence.js

@@ -4,6 +4,7 @@
 const util = require("./utilities");
 const filtering = require("./filtering");
 const misc = require("./misc");
+const deepEqual = require('./deep-equal');
 
 const engine = {};
 engine.emptyFn = util.isEmpty;
@@ -68,62 +69,15 @@ engine.anyFalseFn = function(x) {
 };
 
 
-/**
- * Returns a JSON version of the given object, but with keys of the object in
- * sorted order (or at least a stable order).
- * From: https://stackoverflow.com/a/35810961/360782
- */
-function orderedJsonStringify(obj) {
- return JSON.stringify(sortObjByKey(obj));
-}
-
-/**
- * If given value is an object, returns a new object with the properties added
- * in sorted order, and handles nested objects. Otherwise, returns the given
- * value.
- * From: https://stackoverflow.com/a/35810961/360782
- */
-function sortObjByKey(value) {
- return (typeof value === 'object') ?
- (Array.isArray(value) ?
- value.map(sortObjByKey) :
- Object.keys(value).sort().reduce(
- (o, key) => {
- const v = value[key];
- o[key] = sortObjByKey(v);
- return o;
- }, {})
- ) :
- value;
-}
-
-
 /**
  * Returns true if coll1 is a subset of coll2.
  */
 function subsetOf(coll1, coll2) {
  let rtn = coll1.length <= coll2.length;
  if (rtn) {
- // This requires a deep-equals comparision of every object in coll1,
- // against each object in coll2.
- // Optimize by building a hashmap of JSON versions of the objects.
- var c2Hash = {};
  for (let p=0, pLen=coll1.length; p<pLen && rtn; ++p) {
  let obj1 = util.valData(coll1[p]);
- let obj1Str = orderedJsonStringify(obj1);
- let found = false;
- if (p===0) { // c2Hash is not yet built
- for (let i=0, len=coll2.length; i<len; ++i) {
- // No early return from this loop, because we're building c2Hash.
- let obj2 = util.valData(coll2[i]);
- let obj2Str = orderedJsonStringify(obj2);
- c2Hash[obj2Str] = obj2;
- found = found || (obj1Str === obj2Str);
- }
- }
- else
- found = !!c2Hash[obj1Str];
- rtn = found;
+ rtn = coll2.some(obj2 => deepEqual(obj1, util.valData(obj2)));
  }
  }
  return rtn;
@@ -143,19 +97,13 @@ engine.isDistinctFn = function(x) {
 
 engine.distinctFn = function(x) {
  let unique = [];
- // Since this requires a deep equals, use a hash table (on JSON strings) for
- // efficiency.
  if (x.length > 0) {
- let uniqueHash = {};
- for (let i=0, len=x.length; i<len; ++i) {
- let xObj = x[i];
- let xStr = JSON.stringify(xObj);
- let uObj = uniqueHash[xStr];
- if (uObj === undefined) {
- unique.push(xObj);
- uniqueHash[xStr] = xObj;
- }
- }
+ x = x.concat();
+ do {
+ let xObj = x.shift();
+ unique.push(xObj);
+ x = x.filter(o => !deepEqual(xObj, o));
+ } while (x.length);
  }
  return unique;
 };

src/fhirpath.js

@@ -93,6 +93,7 @@ engine.invocationTable = {
  skip: {fn: filtering.skipFn, arity: {1: ["Integer"]}},
  combine: {fn: combining.combineFn, arity: {1: ["AnyAtRoot"]}},
  union: {fn: combining.union, arity: {1: ["AnyAtRoot"]}},
+ intersect: {fn: combining.intersect, arity: {1: ["AnyAtRoot"]}},
  iif: {fn: misc.iifMacro, arity: {2: ["Expr", "Expr"], 3: ["Expr", "Expr", "Expr"]}},
  trace: {fn: misc.traceFn, arity: {0: [], 1: ["String"]}},
  toInteger: {fn: misc.toInteger},

src/utilities.js

@@ -1,7 +1,7 @@
 // This file holds utility functions used in implementing the public functions.
 
-var util = {};
-var types = require('./types');
+const util = {};
+const types = require('./types');
 let {ResourceNode} = types;
 
 /**

test/cases/3.2_paths.yaml

@@ -50,7 +50,7 @@ tests:
  result: ['medium', 'low', 'zero']
 
  - desc: "QR with where()"
- expression: "contained.where(resourceType = 'QuestionnaireResponse').item.where(linkId = 1).answer.value"
+ expression: "contained.where(resourceType = 'QuestionnaireResponse').item.where(linkId = '1').answer.value"
  model: 'r4'
  result: ['Red']
 

test/cases/5.1_existence.yaml

@@ -326,6 +326,16 @@ tests:
  expression: Functions.coll1[0].coll2.attr.distinct()
  result: [1, 2, 3]
 
+ - desc: '** should not depend on the order of properties in an object'
+ expression: Functions.objects.distinct()
+ result:
+ - prop1: 1
+ prop2: 2
+ - prop1: 3
+ prop2: 4
+ - prop1: 5
+ prop2: 6
+
 
  - desc: '5.1.13. count() : integer'
 # Returns a collection with a single value which is
@@ -410,4 +420,13 @@ subject:
  c:
  e: 6
  d: 5
+ objects:
+ - prop1: 1
+ prop2: 2
+ - prop1: 3
+ prop2: 4
+ - prop2: 2
+ prop1: 1
+ - prop1: 5
+ prop2: 6
 

test/cases/5.3_subsetting.yaml

@@ -171,6 +171,13 @@ tests:
  expression: Functions.coll1.coll2.attr.take(5)
  result: [1, 2, 3, 4, 5]
 
+ - desc: '5.3.8. intersect(other: collection) : collection'
+ - desc: '** should not depend on the order of properties in an object'
+ expression: Functions.objects.group1.intersect(Functions.objects.group2)
+ result:
+ - prop1: 1
+ prop2: 2
+
 subject:
  resourceType: Functions
  attrempty: []
@@ -216,3 +223,14 @@ subject:
  - attr: '@2015-02-04T14:34:28Z'
  - attr: '@T14:34:28+09:00'
  - attr: 4 days
+ objects:
+ group1:
+ - prop1: 1
+ prop2: 2
+ - prop1: 3
+ prop2: 4
+ group2:
+ - prop2: 2
+ prop1: 1
+ - prop1: 5
+ prop2: 6

test/cases/5.4_combining.yaml

@@ -20,6 +20,15 @@ tests:
  expression: Functions.attrdouble | Functions.coll1.coll2.attr
  result: [1, 2, 3, 4, 5]
 
+ - desc: '** should not depend on the order of properties in an object'
+ expression: Functions.objects.group1 | Functions.objects.group2
+ result:
+ - prop1: 1
+ prop2: 2
+ - prop1: 3
+ prop2: 4
+ - prop1: 5
+ prop2: 6
 
  - desc: '5.4.2. combine(other : collection) : collection'
 # Merge the input and other collections into a single collection without eliminating duplicate values. Combining an empty collection with a non-empty collection will return the non-empty collection. There is no expectation of order in the resulting collection.
@@ -85,3 +94,14 @@ subject:
  - attr: '@2015-02-04T14:34:28Z'
  - attr: '@T14:34:28+09:00'
  - attr: 4 days
+ objects:
+ group1:
+ - prop1: 1
+ prop2: 2
+ - prop1: 3
+ prop2: 4
+ group2:
+ - prop2: 2
+ prop1: 1
+ - prop1: 5
+ prop2: 6

test/cases/fhir-r4.yaml

@@ -2833,7 +2833,6 @@ tests:
  expression: 1.combine(1).intersect(1).count() = 1
  result:
  - true
- disable: true
  - 'group: testExclude':
  - desc: '** testExclude1'
  inputfile: patient-example.json