Add support of partial results to the switch expression function

elastic · Aug 10, 2021 · 24ed18e · 24ed18e
1 parent 37a97b4
commit 24ed18e
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Showing 2 changed files with 61 additions and 8 deletions.
diff --git a/x-pack/plugins/canvas/canvas_plugin_src/functions/common/switch.test.js b/x-pack/plugins/canvas/canvas_plugin_src/functions/common/switch.test.js
@@ -108,6 +108,55 @@ describe('switch', () => {
           expectObservable(fn(context, args)).toBe('(0|)', [result])
         );
       });
+
+      it('should support partial results', () => {
+        testScheduler.run(({ cold, expectObservable }) => {
+          const context = 'foo';
+          const case1 = cold('--ab-c-', {
+            a: {
+              type: 'case',
+              matches: false,
+              result: 1,
+            },
+            b: {
+              type: 'case',
+              matches: true,
+              result: 2,
+            },
+            c: {
+              type: 'case',
+              matches: false,
+              result: 3,
+            },
+          });
+          const case2 = cold('-a--bc-', {
+            a: {
+              type: 'case',
+              matches: true,
+              result: 4,
+            },
+            b: {
+              type: 'case',
+              matches: true,
+              result: 5,
+            },
+            c: {
+              type: 'case',
+              matches: true,
+              result: 6,
+            },
+          });
+          const expected = ' --abc(de)-';
+          const args = { case: [() => case1, () => case2] };
+          expectObservable(fn(context, args)).toBe(expected, {
+            a: 4,
+            b: 2,
+            c: 2,
+            d: 5,
+            e: 6,
+          });
+        });
+      });
     });
   });
 });
diff --git a/x-pack/plugins/canvas/canvas_plugin_src/functions/common/switch.ts b/x-pack/plugins/canvas/canvas_plugin_src/functions/common/switch.ts
@@ -5,8 +5,8 @@
  * 2.0.
  */
 
-import { Observable, defer, from, of } from 'rxjs';
-import { concatMap, filter, merge, pluck, take } from 'rxjs/operators';
+import { Observable, combineLatest, defer, of } from 'rxjs';
+import { concatMap } from 'rxjs/operators';
 import { ExpressionFunctionDefinition } from 'src/plugins/expressions/common';
 import { Case } from '../../../types';
 import { getFunctionHelp } from '../../../i18n';
@@ -43,12 +43,16 @@ export function switchFn(): ExpressionFunctionDefinition<
       },
     },
     fn(input, args) {
-      return from(args.case ?? []).pipe(
-        concatMap((item) => item()),
-        filter(({ matches }) => matches),
-        pluck('result'),
-        merge(defer(() => args.default?.() ?? of(input))),
-        take(1)
+      const cases = args.case?.map((item) => defer(() => item())) ?? [];
+      const cases$ = cases.length ? combineLatest(cases) : of([]);
+
+      return cases$.pipe(
+        concatMap((items) => {
+          const item = items.find(({ matches }) => matches);
+          const item$ = item && of(item.result);
+
+          return item$ ?? args.default?.() ?? of(input);
+        })
       );
     },
   };