Make facet supports T as we probably don't want a wildcard for type

Author: kanitw

src/constraint/field.ts

@@ -8,6 +8,7 @@ import {
   ScaleType,
   scaleTypeSupportProperty
 } from 'vega-lite/build/src/scale';
+import {isLocalSingleTimeUnit, isUtcSingleTimeUnit} from 'vega-lite/build/src/timeunit';
 import * as TYPE from 'vega-lite/build/src/type';
 import {QueryConfig} from '../config';
 import {getEncodingNestedProp, Property, SCALE_PROPS} from '../property';
@@ -89,7 +90,19 @@ export const FIELD_CONSTRAINTS: EncodingConstraintModel<FieldQuery>[] = [
         ...toFieldDef(fieldQ, {schema, props: ['bin', 'timeUnit', 'type']})
       };
 
-      return channelCompatibility(fieldDef, fieldQ.channel as Channel).compatible;
+      const {compatible} = channelCompatibility(fieldDef, fieldQ.channel as Channel);
+
+      if (compatible) {
+        return true;
+      } else {
+        // In VL, facet's field def must be discrete (O/N), but in CompassQL we can relax this a bit.
+        const isFacet = fieldQ.channel === 'row' || fieldQ.channel === 'column';
+
+        if (isFacet && (isLocalSingleTimeUnit(fieldDef.timeUnit) || isUtcSingleTimeUnit(fieldDef.timeUnit))) {
+          return true;
+        }
+        return false;
+      }
     }
   },
   {
@@ -242,7 +255,7 @@ export const FIELD_CONSTRAINTS: EncodingConstraintModel<FieldQuery>[] = [
   },
   {
     name: 'typeMatchesPrimitiveType',
-    description: 'Data type should be supported by field\'s primitive type.',
+    description: "Data type should be supported by field's primitive type.",
     properties: [Property.FIELD, Property.TYPE],
     allowWildcardForProperties: false,
     strict: true,
@@ -278,7 +291,7 @@ export const FIELD_CONSTRAINTS: EncodingConstraintModel<FieldQuery>[] = [
   },
   {
     name: 'typeMatchesSchemaType',
-    description: 'Enumerated data type of a field should match the field\'s type in the schema.',
+    description: "Enumerated data type of a field should match the field's type in the schema.",
     properties: [Property.FIELD, Property.TYPE],
     allowWildcardForProperties: false,
     strict: false,

test/constraint/field.test.ts

@@ -384,15 +384,17 @@ describe('constraints/field', () => {
       });
 
       it(channel + ' supports timeUnit temporal dimension.', () => {
-        const encQ: EncodingQuery = {channel: channel, field: 'T', type: TYPE.ORDINAL, timeUnit: TimeUnit.MONTH};
-        assert.isTrue(
-          FIELD_CONSTRAINT_INDEX['channelFieldCompatible'].satisfy(
-            encQ,
-            schema,
-            new PropIndex<Wildcard<any>>(),
-            CONSTRAINT_MANUALLY_SPECIFIED_CONFIG
-          )
-        );
+        for (const type of [TYPE.ORDINAL, TYPE.TEMPORAL]) {
+          const encQ: EncodingQuery = {channel: channel, field: 'T', type, timeUnit: TimeUnit.MONTH};
+          assert.isTrue(
+            FIELD_CONSTRAINT_INDEX['channelFieldCompatible'].satisfy(
+              encQ,
+              schema,
+              new PropIndex<Wildcard<any>>(),
+              CONSTRAINT_MANUALLY_SPECIFIED_CONFIG
+            )
+          );
+        }
       });
 
       it(channel + ' supports binned quantitative dimension.', () => {
@@ -493,7 +495,7 @@ describe('constraints/field', () => {
         );
       });
 
-      it(channel + ' does not support ordinal dimension.', () => {
+      it(channel + ' supports ordinal dimension.', () => {
         const encQ: EncodingQuery = {channel: channel, field: 'O', type: TYPE.ORDINAL};
         assert.isTrue(
           FIELD_CONSTRAINT_INDEX['channelFieldCompatible'].satisfy(
@@ -505,7 +507,7 @@ describe('constraints/field', () => {
         );
       });
 
-      it(channel + ' does not support  nominal dimension.', () => {
+      it(channel + ' does not support nominal dimension.', () => {
         const encQ: EncodingQuery = {channel: channel, field: 'N', type: TYPE.NOMINAL};
         assert.isFalse(
           FIELD_CONSTRAINT_INDEX['channelFieldCompatible'].satisfy(