fix(table-core): compare equal values consistently in greaterThanOrEqualTo and lessThan

.changeset/even-filters-compare.md

@@ -0,0 +1,5 @@
+---
+'@tanstack/table-core': patch
+---
+
+Make `filterFn_greaterThanOrEqualTo` and `filterFn_lessThan` (and the endpoints of `filterFn_between` / `filterFn_betweenInclusive`) treat values as equal using the same normalization as `filterFn_greaterThan`, so `30` equals `'30'`, two `Date`s with the same time are equal, and strings that differ only in case are equal.

packages/table-core/src/features/column-filtering/filterFns.ts

@@ -216,7 +216,8 @@ export const filterFn_greaterThan = constructFilterFn({
 /**
  * Keeps rows whose value is greater than or equal to the filter value.
  *
- * Delegates to the built-in greater-than and strict-equality comparisons.
+ * Equality uses the same normalization as greater-than, so `30` equals `'30'`
+ * and two `Date`s with the same time are equal.
  */
 export const filterFn_greaterThanOrEqualTo = constructFilterFn({
   filter: (dataValue, filterValue) =>
@@ -487,23 +488,35 @@ function toDateTimestamp(value: any): number {
   return new Date(value).getTime()
 }
 
-function compareGreaterThan(dataValue: any, filterValue: any): boolean {
+function compareValues(dataValue: any, filterValue: any): number {
   const numericDataValue = dataValue == null ? 0 : +dataValue
   const numericFilterValue = Number(filterValue)
 
   if (!isNaN(numericFilterValue) && !isNaN(numericDataValue)) {
     return numericDataValue > numericFilterValue
+      ? 1
+      : numericDataValue < numericFilterValue
+        ? -1
+        : 0
   }
 
   const stringDataValue = String(dataValue ?? '')
     .toLowerCase()
     .trim()
   const stringFilterValue = String(filterValue).toLowerCase().trim()
   return stringDataValue > stringFilterValue
+    ? 1
+    : stringDataValue < stringFilterValue
+      ? -1
+      : 0
+}
+
+function compareGreaterThan(dataValue: any, filterValue: any): boolean {
+  return compareValues(dataValue, filterValue) > 0
 }
 
 function compareGreaterThanOrEqualTo(dataValue: any, filterValue: any) {
-  return dataValue === filterValue || compareGreaterThan(dataValue, filterValue)
+  return compareValues(dataValue, filterValue) >= 0
 }
 
 function compareBetween(

packages/table-core/tests/unit/fns/filterFns.test.ts

@@ -512,6 +512,38 @@ describe('Filter Functions', () => {
         expect(result).toBe(true)
       })
     })
+    describe('equal values compared the way greaterThan compares them', () => {
+      const makeRow = (value: unknown) => ({ getValue: () => value }) as any
+
+      it('treats a numeric string filter value as equal to the number', () => {
+        const row = mockRows[0]! // age 30
+        expect(filterFn_greaterThanOrEqualTo(row, 'age', '30')).toBe(true)
+        expect(filterFn_lessThan(row, 'age', '30')).toBe(false)
+      })
+
+      it('treats two Date instances with the same time as equal', () => {
+        const row = makeRow(new Date(2024, 0, 15))
+        const filterValue = new Date(2024, 0, 15)
+        expect(filterFn_greaterThanOrEqualTo(row, 'date', filterValue)).toBe(
+          true,
+        )
+        expect(filterFn_lessThan(row, 'date', filterValue)).toBe(false)
+      })
+
+      it('treats strings that differ only in case as equal', () => {
+        const row = mockRows[0]! // firstName 'John'
+        expect(filterFn_greaterThanOrEqualTo(row, 'firstName', 'john')).toBe(
+          true,
+        )
+        expect(filterFn_lessThan(row, 'firstName', 'john')).toBe(false)
+      })
+
+      it('applies the same equality to range endpoints', () => {
+        const row = mockRows[0]! // age 30
+        expect(filterFns.betweenInclusive(row, 'age', ['30', '40'])).toBe(true)
+        expect(filterFns.between(row, 'age', ['20', '30'])).toBe(false)
+      })
+    })
   })
 
   describe('Range Filters', () => {