docs: add docs for rangeCheck function.

Author: ghosind

src/utils.ts

@@ -1,15 +1,5 @@
 import { DynamicBuffer } from './dynamicBuffer';
 
-export const rangeCheck = (field: string, value: number, min?: number, max?: number) => {
-  if (min !== undefined && value < min) {
-    throw RangeError(`The value of '${field}' is out of range. It must be >= ${min}. Received ${value}`);
-  }
-
-  if (max !== undefined && value > max) {
-    throw RangeError(`The value of '${field}' is out of range. It must be <= ${max}. Received ${value}`);
-  }
-};
-
 /**
  * Returns true if obj is a DynamicBuffer, false otherwise.
  *
@@ -24,6 +14,24 @@ export const rangeCheck = (field: string, value: number, min?: number, max?: num
  */
 export const isDynamicBuffer = (val: any) => val instanceof DynamicBuffer;
 
+/**
+ * Check the value in the required range, and throw an error if not satisfy the range requirement.
+ *
+ * @param field The field name.
+ * @param value The value to check.
+ * @param min The allowed minimum value (included) of this value.
+ * @param max The allowed maximum value (included) of this value.
+ */
+export const rangeCheck = (field: string, value: number, min?: number, max?: number) => {
+  if (min !== undefined && value < min) {
+    throw RangeError(`The value of '${field}' is out of range. It must be >= ${min}. Received ${value}`);
+  }
+
+  if (max !== undefined && value > max) {
+    throw RangeError(`The value of '${field}' is out of range. It must be <= ${max}. Received ${value}`);
+  }
+};
+
 /**
  * Swap two element in the buffer.
  */