diff --git a/src/index.ts b/src/index.ts
index 1942ecbac..0d1244f24 100644
--- a/src/index.ts
+++ b/src/index.ts
@@ -6,7 +6,15 @@ import bindGlobalEventListeners, {
 } from './bindGlobalEventListeners';
 import {getArrayOfElements, isReferenceElement, isElement} from './utils';
 import {warnWhen, validateTargets, validateProps} from './validation';
-import {Props, Instance, Targets, HideAllOptions, Plugin, Tippy} from './types';
+import {
+  Props,
+  Instance,
+  Targets,
+  HideAllOptions,
+  Plugin,
+  Tippy,
+  DefaultProps,
+} from './types';
 
 /**
  * Exported module
@@ -68,7 +76,7 @@ tippy.currentInput = currentInput;
 /**
  * Mutates the defaultProps object by setting the props specified
  */
-function setDefaultProps(partialProps: Partial<Props>): void {
+function setDefaultProps(partialProps: Partial<DefaultProps>): void {
   if (__DEV__) {
     validateProps(partialProps, []);
   }
diff --git a/src/props.ts b/src/props.ts
index f676f9736..4e712bd53 100644
--- a/src/props.ts
+++ b/src/props.ts
@@ -1,6 +1,6 @@
-import {Props, Plugin} from './types';
+import {Props, DefaultProps, Plugin} from './types';
 
-export const defaultProps: Props = {
+export const defaultProps: DefaultProps = {
   allowHTML: true,
   animation: 'fade',
   appendTo: (): Element => document.body,
diff --git a/src/types.ts b/src/types.ts
index 73fed53f3..1568c7b21 100644
--- a/src/types.ts
+++ b/src/types.ts
@@ -47,9 +47,9 @@ export interface Props extends LifecycleHooks {
   arrow: boolean | string | SVGElement;
   boundary: 'scrollParent' | 'window' | 'viewport' | HTMLElement;
   content: Content;
-  delay: number | [number, number];
+  delay: number | [number | null, number | null];
   distance: number | string;
-  duration: number | [number, number];
+  duration: number | [number | null, number | null];
   flip: boolean;
   flipBehavior: 'flip' | Placement[];
   flipOnUpdate: boolean;
@@ -76,6 +76,11 @@ export interface Props extends LifecycleHooks {
   [key: string]: any;
 }
 
+export interface DefaultProps extends Props {
+  delay: number | [number, number];
+  duration: number | [number, number];
+}
+
 export interface AnimateFillProps {
   animateFill: boolean;
 }
diff --git a/src/utils.ts b/src/utils.ts
index 153af8e76..69e4ace8f 100644
--- a/src/utils.ts
+++ b/src/utils.ts
@@ -38,9 +38,9 @@ export function getArrayOfElements(value: Targets): Element[] {
  * Returns a value at a given index depending on if it's an array or number
  */
 export function getValueAtIndexOrReturn<T>(
-  value: T | T[],
+  value: T | [T | null, T | null],
   index: number,
-  defaultValue: T | T[],
+  defaultValue: T | [T, T],
 ): T {
   if (Array.isArray(value)) {
     const v = value[index];