[tests] 100% coverage

Author: jamesgpearce

src/common/array.ts

@@ -41,9 +41,9 @@ export const arrayJoin = (array: string[], sep = EMPTY_STRING) =>
   array.join(sep);
 
 export const arrayMap = <Value, Return>(
-  array: Value[] | undefined,
+  array: Value[],
   cb: (value: Value, index: number, array: Value[]) => Return,
-): Return[] => array?.map(cb) ?? [];
+): Return[] => array.map(cb);
 
 export const arraySum = (array: number[]): number =>
   arrayReduce<number, number>(array, (i, j) => i + j, 0);

src/ui-react-dom/index.tsx

@@ -266,7 +266,7 @@ const useCells = (
 const extraKey = (index: number, after: 0 | 1) => (after ? '>' : '<') + index;
 
 const extraHeaders = (
-  extraCells: (ExtraRowCell | ExtraValueCell)[] | undefined,
+  extraCells: (ExtraRowCell | ExtraValueCell)[] = [],
   after: 0 | 1 = 0,
 ) =>
   arrayMap(extraCells, ({label}, index) => (
@@ -276,7 +276,7 @@ const extraHeaders = (
   ));
 
 const extraRowCells = (
-  extraRowCells: ExtraRowCell[] | undefined,
+  extraRowCells: ExtraRowCell[] = [],
   extraRowCellProps: RowProps,
   after: 0 | 1 = 0,
 ) =>
@@ -287,7 +287,7 @@ const extraRowCells = (
   ));
 
 const extraValueCells = (
-  extraValueCells: ExtraValueCell[] | undefined,
+  extraValueCells: ExtraValueCell[] = [],
   extraValueCellProps: ValueProps,
   after: 0 | 1 = 0,
 ) =>