fix interpolate checks

Author: birkskyum

src/expression/definitions/interpolate.ts

@@ -174,17 +174,17 @@ class Interpolate implements Expression {
         const outputLower = outputs[index].evaluate(ctx);
         const outputUpper = outputs[index + 1].evaluate(ctx);
 
-        if (this.type.kind == 'projection') {
-            return interpolate.projection(outputLower, outputUpper, t);
-        }
 
         switch (this.operator) {
             case 'interpolate':
-                return interpolate[this.type.kind](outputLower, outputUpper, t);
+                return interpolate[this.type.kind.toString()](outputLower, outputUpper, t);
             case 'interpolate-hcl':
                 return interpolate.color(outputLower, outputUpper, t, 'hcl');
             case 'interpolate-lab':
                 return interpolate.color(outputLower, outputUpper, t, 'lab');
+            case 'interpolate-projection': {
+                return interpolate.projection(outputLower, outputUpper, t);
+            }
         }
     }
 

src/validate/validate_projectionconfig.test.ts

@@ -41,8 +41,8 @@ describe('Validate projectionConfig', () => {
         expect(errors).toHaveLength(0);
     });
 
-    test('should parse iterpolate-projectionConfig', () => {
-        const errors = validateProjectionConfig({validateSpec, value: {'type': ['interpolate-projectionConfig', ['linear'], ['zoom'], 0, 'mercator', 5, 'vertical-perspective']}, styleSpec: v8, style: {} as any});
+    test('should parse iterpolate-projection', () => {
+        const errors = validateProjectionConfig({validateSpec, value: {'type': ['interpolate-projection', ['linear'], ['zoom'], 0, 'mercator', 5, 'vertical-perspective']}, styleSpec: v8, style: {} as any});
         expect(errors).toHaveLength(0);
     });