Refactor, cleanup

lib/space_lua/util.ts

@@ -0,0 +1,92 @@
+export function evalPromiseValues(vals: any[]): Promise<any[]> | any[] {
+  const promises = [];
+  const promiseResults = new Array(vals.length);
+  for (let i = 0; i < vals.length; i++) {
+    if (vals[i] instanceof Promise) {
+      promises.push(vals[i].then((v: any) => promiseResults[i] = v));
+    } else {
+      promiseResults[i] = vals[i];
+    }
+  }
+  if (promises.length === 0) {
+    return promiseResults;
+  } else {
+    return Promise.all(promises).then(() => promiseResults);
+  }
+}
+
+/**
+ * return the mid value among x, y, and z
+ * @param x
+ * @param y
+ * @param z
+ * @param compare
+ * @returns {Promise.<*>}
+ */
+async function getPivot(
+  x: any,
+  y: any,
+  z: any,
+  compare: (a: any, b: any) => Promise<number>,
+) {
+  if (await compare(x, y) < 0) {
+    if (await compare(y, z) < 0) {
+      return y;
+    } else if (await compare(z, x) < 0) {
+      return x;
+    } else {
+      return z;
+    }
+  } else if (await compare(y, z) > 0) {
+    return y;
+  } else if (await compare(z, x) > 0) {
+    return x;
+  } else {
+    return z;
+  }
+}
+
+/**
+ * asynchronous quick sort
+ * @param arr array to sort
+ * @param compare asynchronous comparing function
+ * @param left index where the range of elements to be sorted starts
+ * @param right index where the range of elements to be sorted ends
+ * @returns {Promise.<*>}
+ */
+export async function asyncQuickSort(
+  arr: any[],
+  compare: (a: any, b: any) => Promise<number>,
+  left = 0,
+  right = arr.length - 1,
+) {
+  if (left < right) {
+    let i = left, j = right, tmp;
+    const pivot = await getPivot(
+      arr[i],
+      arr[i + Math.floor((j - i) / 2)],
+      arr[j],
+      compare,
+    );
+    while (true) {
+      while (await compare(arr[i], pivot) < 0) {
+        i++;
+      }
+      while (await compare(pivot, arr[j]) < 0) {
+        j--;
+      }
+      if (i >= j) {
+        break;
+      }
+      tmp = arr[i];
+      arr[i] = arr[j];
+      arr[j] = tmp;
+
+      i++;
+      j--;
+    }
+    await asyncQuickSort(arr, compare, left, i - 1);
+    await asyncQuickSort(arr, compare, j + 1, right);
+  }
+  return arr;
+}