[reactstrap] Don't declare "popper.js" module, prevent TypeScript conflict error (#22680)

* [reactstrap] Define Popper.js only internally

* [reactstrap] Switching 'declare namespace' to 'export as namespace'

types/reactstrap/lib/Popover.d.ts

@@ -1,7 +1,7 @@
 /// <reference types='react' />
-/// <reference path="./Popper.d.ts" />
 
 import { CSSModule } from '../index';
+import {Popper} from './Popper';
 
 export interface PopoverProps extends React.HTMLAttributes<HTMLElement> {
   isOpen?: boolean;

types/reactstrap/lib/Popper.d.ts

@@ -6,128 +6,129 @@
 // It should not define internal pieces such as utils or modifier details.
 // It has been copied from: https://raw.githubusercontent.com/FezVrasta/popper.js/master/packages/popper/index.d.ts
 
-declare namespace Popper {
-    export type Position = 'top' | 'right' | 'bottom' | 'left';
+export as namespace Popper;
 
-    export type Placement = 'auto-start'
-      | 'auto'
-      | 'auto-end'
-      | 'top-start'
-      | 'top'
-      | 'top-end'
-      | 'right-start'
-      | 'right'
-      | 'right-end'
-      | 'bottom-end'
-      | 'bottom'
-      | 'bottom-start'
-      | 'left-end'
-      | 'left'
-      | 'left-start';
+export type Position = "top" | "right" | "bottom" | "left";
 
-    export type Boundary = 'scrollParent' | 'viewport' | 'window';
+export type Placement =
+    | "auto-start"
+    | "auto"
+    | "auto-end"
+    | "top-start"
+    | "top"
+    | "top-end"
+    | "right-start"
+    | "right"
+    | "right-end"
+    | "bottom-end"
+    | "bottom"
+    | "bottom-start"
+    | "left-end"
+    | "left"
+    | "left-start";
 
-    export type ModifierFn = (data: Data, options: Object) => Data;
+export type Boundary = "scrollParent" | "viewport" | "window";
 
-    export interface BaseModifier {
-      order?: number;
-      enabled?: boolean;
-      fn?: ModifierFn;
-    }
+export type ModifierFn = (data: Data, options: Object) => Data;
 
-    export interface Modifiers {
-      shift?: BaseModifier;
-      offset?: BaseModifier & {
-        offset?: number | string,
-      };
-      preventOverflow?: BaseModifier & {
-        priority?: Position[],
-        padding?: number,
-        boundariesElement?: Boundary | Element,
-        escapeWithReference?: boolean
-      };
-      keepTogether?: BaseModifier;
-      arrow?: BaseModifier & {
-        element?: string | Element,
-      };
-      flip?: BaseModifier & {
-        behavior?: 'flip' | 'clockwise' | 'counterclockwise' | Position[],
-        padding?: number,
-        boundariesElement?: Boundary | Element,
-      };
-      inner?: BaseModifier;
-      hide?: BaseModifier;
-      applyStyle?: BaseModifier & {
-        onLoad?: Function,
-        gpuAcceleration?: boolean,
-      };
-      computeStyle?: BaseModifier & {
-          gpuAcceleration?: boolean;
-          x?: 'bottom' | 'top',
-          y?: 'left' | 'right'
-      };
-      [name: string]: (BaseModifier & Record<string, any>) | undefined;
-    }
+export interface BaseModifier {
+    order?: number;
+    enabled?: boolean;
+    fn?: ModifierFn;
+}
 
-    export interface Offset {
-      top: number;
-      left: number;
-      width: number;
-      height: number;
-    }
+export interface Modifiers {
+    shift?: BaseModifier;
+    offset?: BaseModifier & {
+        offset?: number | string;
+    };
+    preventOverflow?: BaseModifier & {
+        priority?: Position[];
+        padding?: number;
+        boundariesElement?: Boundary | Element;
+        escapeWithReference?: boolean;
+    };
+    keepTogether?: BaseModifier;
+    arrow?: BaseModifier & {
+        element?: string | Element;
+    };
+    flip?: BaseModifier & {
+        behavior?: "flip" | "clockwise" | "counterclockwise" | Position[];
+        padding?: number;
+        boundariesElement?: Boundary | Element;
+    };
+    inner?: BaseModifier;
+    hide?: BaseModifier;
+    applyStyle?: BaseModifier & {
+        onLoad?: Function;
+        gpuAcceleration?: boolean;
+    };
+    computeStyle?: BaseModifier & {
+        gpuAcceleration?: boolean;
+        x?: "bottom" | "top";
+        y?: "left" | "right";
+    };
+    [name: string]: (BaseModifier & Record<string, any>) | undefined;
+}
 
-    export interface Data {
-      instance: Popper;
-      placement: Placement;
-      originalPlacement: Placement;
-      flipped: boolean;
-      hide: boolean;
-      arrowElement: Element;
-      styles: CSSStyleDeclaration;
-      boundaries: Object;
-      offsets: {
-        popper: Offset,
-        reference: Offset,
+export interface Offset {
+    top: number;
+    left: number;
+    width: number;
+    height: number;
+}
+
+export interface Data {
+    instance: Popper;
+    placement: Placement;
+    originalPlacement: Placement;
+    flipped: boolean;
+    hide: boolean;
+    arrowElement: Element;
+    styles: CSSStyleDeclaration;
+    boundaries: Object;
+    offsets: {
+        popper: Offset;
+        reference: Offset;
         arrow: {
-          top: number,
-          left: number,
-        },
-      };
-    }
+            top: number;
+            left: number;
+        };
+    };
+}
 
-    export interface PopperOptions {
-      placement?: Placement;
-      positionFixed: boolean;
-      eventsEnabled?: boolean;
-      modifiers?: Modifiers;
-      removeOnDestroy?: boolean;
-      onCreate?(data: Data): void;
-      onUpdate?(data: Data): void;
-    }
+export interface PopperOptions {
+    placement?: Placement;
+    positionFixed: boolean;
+    eventsEnabled?: boolean;
+    modifiers?: Modifiers;
+    removeOnDestroy?: boolean;
+    onCreate?(data: Data): void;
+    onUpdate?(data: Data): void;
+}
 
-    export interface ReferenceObject {
-      clientHeight: number;
-      clientWidth: number;
-      getBoundingClientRect(): ClientRect;
-    }
-  }
+export interface ReferenceObject {
+    clientHeight: number;
+    clientWidth: number;
+    getBoundingClientRect(): ClientRect;
+}
 
-  declare class Popper {
+export class Popper {
     static modifiers: (Popper.BaseModifier & { name: string })[];
     static placements: Popper.Placement[];
     static Defaults: Popper.PopperOptions;
 
     options: Popper.PopperOptions;
 
-    constructor(reference: Element | Popper.ReferenceObject, popper: Element, options?: Popper.PopperOptions);
+    constructor(
+        reference: Element | Popper.ReferenceObject,
+        popper: Element,
+        options?: Popper.PopperOptions
+    );
 
     destroy(): void;
     update(): void;
     scheduleUpdate(): void;
     enableEventListeners(): void;
     disableEventListeners(): void;
-  }
-
-  declare module 'popper.js' {
-    export default Popper;
-  }
+}

types/reactstrap/lib/Tooltip.d.ts

@@ -1,7 +1,7 @@
 /// <reference types='react' />
-/// <reference path="./Popper.d.ts" />
 
 import { CSSModule } from '../index';
+import {Popper} from './Popper';
 
 export interface UncontrolledProps extends React.HTMLAttributes<HTMLElement> {
   target: string | HTMLElement;