@@ -0,0 +1,46 @@
+function interpolationSearch(sortedArray, seekElement) {
+  let leftIndex = 0;
+  let rightIndex = sortedArray.length - 1;
+
+  while (leftIndex <= rightIndex) {
+    const rangeDelta = sortedArray[rightIndex] - sortedArray[leftIndex];
+    const indexDelta = rightIndex - leftIndex;
+    const valueDelta = seekElement - sortedArray[leftIndex];
+
+    // If valueDelta is less then zero it means that there is no seek element
+    // exists in array since the lowest element from the range is already higher
+    // then seek element.
+    if (valueDelta < 0) {
+      return -1;
+    }
+
+    // If range delta is zero then subarray contains all the same numbers
+    // and thus there is nothing to search for unless this range is all
+    // consists of seek number.
+    if (!rangeDelta) {
+      // By doing this we're also avoiding division by zero while
+      // calculating the middleIndex later.
+      return sortedArray[leftIndex] === seekElement ? leftIndex : -1;
+    }
+
+    // Do interpolation of the middle index.
+    const middleIndex = leftIndex + Math.floor(valueDelta * indexDelta / rangeDelta);
+
+    // If we've found the element just return its position.
+    if (sortedArray[middleIndex] === seekElement) {
+      return middleIndex;
+    }
+
+    // Decide which half to choose for seeking next: left or right one.
+    if (sortedArray[middleIndex] < seekElement) {
+      // Go to the right half of the array.
+      leftIndex = middleIndex + 1;
+    } else {
+      // Go to the left half of the array.
+      rightIndex = middleIndex - 1;
+    }
+  }
+  return -1;
+}
+
+console.log(interpolationSearch([1,2,3,4,5], 3));