"geometry-type" to identify Multi- features

src/expression/compound_expression.ts

@@ -461,7 +461,7 @@ CompoundExpression.register(expressions, {
     'filter-type-==': [
         BooleanType,
         [StringType],
-        (ctx, [v]) => ctx.geometryType() === (v as any).value
+        (ctx, [v]) => ctx.geometryDollarType() === (v as any).value
     ],
     'filter-<': [
         BooleanType,
@@ -548,7 +548,7 @@ CompoundExpression.register(expressions, {
     'filter-type-in': [
         BooleanType,
         [array(StringType)],
-        (ctx, [v]) => (v as any).value.indexOf(ctx.geometryType()) >= 0
+        (ctx, [v]) => (v as any).value.indexOf(ctx.geometryDollarType()) >= 0
     ],
     'filter-id-in': [
         BooleanType,

src/expression/definitions/within.ts

@@ -192,9 +192,9 @@ class Within implements Expression {
 
     evaluate(ctx: EvaluationContext) {
         if (ctx.geometry() != null && ctx.canonicalID() != null) {
-            if (ctx.geometryType() === 'Point') {
+            if (ctx.geometryDollarType() === 'Point') {
                 return pointsWithinPolygons(ctx, this.geometries);
-            } else if (ctx.geometryType() === 'LineString') {
+            } else if (ctx.geometryDollarType() === 'LineString') {
                 return linesWithinPolygons(ctx, this.geometries);
             }
         }

src/expression/evaluation_context.ts

@@ -2,8 +2,18 @@ import {Color} from './values';
 import type {FormattedSection} from './types/formatted';
 import type {GlobalProperties, Feature, FeatureState} from './index';
 import {ICanonicalTileID} from '../tiles_and_coordinates';
+import {calculateSignedArea} from '../util/classify_rings';
 
 const geometryTypes = ['Unknown', 'Point', 'LineString', 'Polygon'];
+const simpleGeometryType = {
+    'Unknown': 'Unknown',
+    'Point': 'Point',
+    'MultiPoint': 'Point',
+    'LineString': 'LineString',
+    'MultiLineString': 'LineString',
+    'Polygon': 'Polygon',
+    'MultiPolygon': 'Polygon'
+};
 
 class EvaluationContext {
     globals: GlobalProperties;
@@ -14,6 +24,7 @@ class EvaluationContext {
     canonical: ICanonicalTileID;
 
     _parseColorCache: {[_: string]: Color};
+    _geometryType: string;
 
     constructor() {
         this.globals = null;
@@ -29,8 +40,41 @@ class EvaluationContext {
         return this.feature && 'id' in this.feature ? this.feature.id : null;
     }
 
+    geometryDollarType() {
+        return this.feature ?
+            typeof this.feature.type === 'number' ? geometryTypes[this.feature.type] : simpleGeometryType[this.feature.type] :
+            null;
+    }
+
     geometryType() {
-        return this.feature ? typeof this.feature.type === 'number' ? geometryTypes[this.feature.type] : this.feature.type : null;
+        let geometryType = this.feature.type;
+        if (typeof geometryType !== 'number') {
+            return geometryType;
+        }
+        geometryType = geometryTypes[this.feature.type];
+        if (geometryType === 'Unknown') {
+            return geometryType;
+        }
+        const geom = this.geometry();
+        const len = geom.length;
+        if (len === 1) {
+            return geometryType;
+        }
+        if (geometryType !== 'Polygon') {
+            return `Multi${geometryType}`;
+        }
+        // Following https://github.com/mapbox/vector-tile-js/blob/77851380b63b07fd0af3d5a3f144cc86fb39fdd1/lib/vectortilefeature.js#L197
+        for (let i = 0, ccw; i < len; i++) {
+            const area = calculateSignedArea(geom[i]);
+            if (area === 0) continue;
+            if (ccw === undefined) {
+                ccw = area < 0;
+            } else if (ccw === area < 0) {
+                // Same direction as the first ring -> a second outer ring
+                return 'MultiPolygon';
+            }
+        }
+        return geometryType;
     }
 
     geometry() {

src/feature_filter/convert.ts

@@ -128,7 +128,7 @@ function runtimeTypeChecks(expectedTypes: ExpectedTypes): ExpressionFilterSpecif
 function convertComparisonOp(property: string, value: any, op: string, expectedTypes?: ExpectedTypes | null): ExpressionFilterSpecification {
     let get;
     if (property === '$type') {
-        return [op, ['geometry-type'], value] as ExpressionFilterSpecification;
+        return convertInOp('$type', [value], op === '!=');
     } else if (property === '$id') {
         get = ['id'];
     } else {
@@ -162,6 +162,10 @@ function convertInOp(property: string, values: Array<any>, negate = false): Expr
 
     let get: ExpressionSpecification;
     if (property === '$type') {
+        const len = values.length;
+        for (let i = 0; i < len; i++) {
+            values.push(`Multi${values[i]}`);
+        }
         get = ['geometry-type'];
     } else if (property === '$id') {
         get = ['id'];