Add format support & fix test

Author: ssharif6

src/property.ts

@@ -50,7 +50,7 @@ const ENCODING_TOPLEVEL_PROP_INDEX: Flag<EncodingTopLevelProp> = {
   aggregate: 1, autoCount: 1, bin: 1, timeUnit: 1, hasFn: 1,
   sort: 1, stack: 1,
   field: 1, type: 1,
-  scale: 1, axis: 1, legend: 1,
+  format: 1, scale: 1, axis: 1, legend: 1,
   value: 1
 };
 
@@ -174,6 +174,9 @@ export namespace Property {
   export const TRANSFORM: 'transform' = 'transform';
   // Layout
   export const STACK: 'stack' = 'stack';
+
+  export const FORMAT: 'format' = 'format';
+
   // TODO: sub parts of stack
 
   // Encoding Properties

src/query/encoding.ts

@@ -102,6 +102,8 @@ export interface FieldQueryBase {
 
   axis?: boolean | AxisQuery | SHORT_WILDCARD;
   legend?: boolean | LegendQuery | SHORT_WILDCARD;
+
+  format?: string;
 }
 
 export type FieldQuery = EncodingQueryBase & FieldQueryBase;
@@ -119,7 +121,7 @@ export type ScaleQuery =  FlatQueryWithEnableFlag<Scale>;
 export type AxisQuery =  FlatQueryWithEnableFlag<Axis>;
 export type LegendQuery = FlatQueryWithEnableFlag<Legend>;
 
-const DEFAULT_PROPS = [Property.AGGREGATE, Property.BIN, Property.TIMEUNIT, Property.FIELD, Property.TYPE, Property.SCALE, Property.SORT, Property.AXIS, Property.LEGEND, Property.STACK];
+const DEFAULT_PROPS = [Property.AGGREGATE, Property.BIN, Property.TIMEUNIT, Property.FIELD, Property.TYPE, Property.SCALE, Property.SORT, Property.AXIS, Property.LEGEND, Property.STACK, Property.FORMAT];
 
 export interface ConversionParams {
   schema?: Schema;

src/wildcard.ts

@@ -107,6 +107,7 @@ export const DEFAULT_NAME = {
   sort: 'so',
   stack: 'st',
   scale: 's',
+  format: 'f',
   axis: 'ax',
   legend: 'l',
   value: 'v',
@@ -164,6 +165,7 @@ export type EnumIndex =
   {
     sort: (SortField<string> | SortOrder)[],
     stack: StackOffset[],
+    format: string[],
     scale: boolean[],
     axis: boolean[],
     legend: boolean[],
@@ -282,6 +284,7 @@ export const DEFAULT_ENUM_INDEX: EnumIndex = {
   stack: ['zero', 'normalize', 'center', null],
   value: [undefined],
 
+  format: [undefined],
   scale: [true],
   axis: DEFAULT_BOOLEAN_ENUM,
   legend: DEFAULT_BOOLEAN_ENUM,

test/query/encoding.test.ts

@@ -24,6 +24,16 @@ describe('query/encoding', () => {
         {type: 'quantitative'}
       );
     });
+
+    it('return correct fieldDef for Text FieldQuery with format', () => {
+      assert.deepEqual(
+        toFieldDef(
+          {format: '.3f', channel: 'text', field: 'Q', type: 'quantitative'},
+          {props: ['field', 'format', 'type'], wildcardMode: 'skip'}
+        ),
+        {format: '.3f', field: 'Q', type: 'quantitative'}
+      );
+    });
   });
 
   describe('toValueDef', () => {