feat: add reverseIfNeeded

Author: lpatiny

src/FilterXYType.ts

@@ -22,6 +22,7 @@ import {
   CalibrateFilter,
   ParetoNormalizationFilter,
 } from './filters/filters';
+import { ReverseIfNeededFilter } from './filters/x/reverseIfNeeded';
 
 export type FilterXYType =
   | AirPLSBaselineFilter
@@ -45,4 +46,5 @@ export type FilterXYType =
   | XFunctionFilter
   | YFunctionFilter
   | CalibrateFilter
-  | ParetoNormalizationFilter;
+  | ParetoNormalizationFilter
+  | ReverseIfNeededFilter;

src/__tests__/filterXY.test.ts

@@ -17,4 +17,30 @@ describe('filterXY', () => {
       y: Float64Array.from([-1, 0, 1, 2, 1, 0, -1]),
     });
   });
+
+  it('reverseIfNeeded, not needed', () => {
+    const filters: FilterXYType[] = [{ name: 'reverseIfNeeded' }];
+    const data = {
+      x: Float64Array.from([1, 2, 3, 4, 5]),
+      y: Float64Array.from([1, 2, 3, 4, 1]),
+    };
+    const result = filterXY(data, filters);
+    expect(result.data).toStrictEqual({
+      x: Float64Array.from([1, 2, 3, 4, 5]),
+      y: Float64Array.from([1, 2, 3, 4, 1]),
+    });
+  });
+
+  it('reverseIfNeeded, needed', () => {
+    const filters: FilterXYType[] = [{ name: 'reverseIfNeeded' }];
+    const data = {
+      x: Float64Array.from([5, 4, 3, 2, 1]),
+      y: Float64Array.from([1, 2, 3, 4, 1]),
+    };
+    const result = filterXY(data, filters);
+    expect(result.data).toStrictEqual({
+      x: Float64Array.from([1, 2, 3, 4, 5]),
+      y: Float64Array.from([1, 4, 3, 2, 1]),
+    });
+  });
 });

src/filterXY.ts

@@ -1,5 +1,5 @@
 import { DataXY } from 'cheminfo-types';
-import { xEnsureFloat64 } from 'ml-spectra-processing';
+import { xEnsureFloat64, xyGrowingX } from 'ml-spectra-processing';
 
 import { FilterXYType } from './FilterXYType';
 import * as Filters from './filters/filters';
@@ -12,7 +12,7 @@ import * as Filters from './filters/filters';
  */
 export function filterXY(data: DataXY, filters: FilterXYType[]) {
   let result = {
-    data: { x: xEnsureFloat64(data.x), y: xEnsureFloat64(data.y) },
+    data: xyGrowingX({ x: xEnsureFloat64(data.x), y: xEnsureFloat64(data.y) }),
   };
 
   const logs = [];
@@ -26,6 +26,7 @@ export function filterXY(data: DataXY, filters: FilterXYType[]) {
     }
     // @ts-expect-error some method have options and some other ones don't have any options
     result = filterFct(result.data, filter.options);
+    result.data = xyGrowingX(result.data);
     logs.push({
       name: filter.name,
       time: Date.now() - start,

src/filters/filters.ts

@@ -18,6 +18,7 @@ export * from './sg/thirdDerivative';
 export * from './sg/savitzkyGolay';
 
 export * from './x/ensureGrowing';
+export * from './x/reverseIfNeeded';
 export * from './x/equallySpaced';
 export * from './x/filterX';
 export * from './x/calibrateX';

src/filters/x/reverseIfNeeded.ts

@@ -0,0 +1,15 @@
+import { DataXY } from 'cheminfo-types';
+import { xyGrowingX } from 'ml-spectra-processing';
+
+export interface ReverseIfNeededFilter {
+  name: 'reverseIfNeeded';
+}
+
+/**
+ * Ensure X values are strictly monotonic increasing
+ * http://www-groups.mcs.st-andrews.ac.uk/~john/analysis/Lectures/L8.html
+ * @param data
+ */
+export function reverseIfNeeded(data: DataXY<Float64Array>) {
+  return { data: xyGrowingX(data) };
+}