feat: add xMinMaxDelta

src/index.ts

@@ -35,6 +35,7 @@ export * from './x/xMedian';
 export * from './x/xMedianAbsoluteDeviation';
 export * from './x/xMinIndex';
 export * from './x/xMinMaxValues';
+export * from './x/xMinMaxDelta';
 export * from './x/xMinValue';
 export * from './x/xMode';
 export * from './x/xMultiply';

src/x/__tests__/xMinMaxDelta.test.ts

@@ -0,0 +1,13 @@
+import { xMinMaxDelta } from '../xMinMaxDelta';
+
+test('xMinMaxDelta', () => {
+  let typedArray = new Uint16Array(6);
+  typedArray[0] = 1;
+  typedArray[1] = 2;
+  typedArray[2] = 3;
+  typedArray[3] = 4;
+  typedArray[4] = 6;
+  typedArray[5] = 7;
+
+  expect(xMinMaxDelta(typedArray)).toStrictEqual({ min: 1, max: 2 });
+});

src/x/xMinMaxDelta.ts

@@ -0,0 +1,27 @@
+import { NumberArray } from 'cheminfo-types';
+
+import { xCheck } from './xCheck';
+
+/**
+ * Return min and max values of an array
+ *
+ * @param array - array of number
+ * @returns - Object with 2 properties, min and max
+ */
+export function xMinMaxDelta(array: NumberArray): {
+  min: number;
+  max: number;
+} {
+  xCheck(array, { minLength: 2 });
+
+  let minDelta = array[1] - array[0];
+  let maxDelta = minDelta;
+
+  for (let i = 0; i < array.length - 1; i++) {
+    let delta = array[i + 1] - array[i];
+    if (delta < minDelta) minDelta = delta;
+    if (delta > maxDelta) maxDelta = delta;
+  }
+
+  return { min: minDelta, max: maxDelta };
+}