feat: merge initial options with action options

README.md

@@ -24,9 +24,9 @@ Since Svelte automatically bundles all required dependencies, you only need to i
 
 ## Usage
 
-`createPopperActions` returns a pair of actions to be used on the [reference and popper elements](https://popper.js.org/docs/v2/constructors/#usage).
+`createPopperActions` takes an optional [options object](https://popper.js.org/docs/v2/constructors/#options) for configuring the popper instance, and returns a pair of actions to be used on the [reference and popper elements](https://popper.js.org/docs/v2/constructors/#usage).
 
-The content action takes an [options object](https://popper.js.org/docs/v2/constructors/#options) for configuring the popper instance.
+The content action also takes an [options object](https://popper.js.org/docs/v2/constructors/#options) for updating the options of the popper instance.
 
 ### Example
 
@@ -62,6 +62,22 @@ A Svelte version of the standard [tutorial](https://popper.js.org/docs/v2/tutori
 
 ## API
 
+### Setting popper options
+
+Popper options can be set statically when creating the popper actions, or dynamically on the content action.
+
+If both are set, then the dynamic options will be merged with the initial options.
+
+```svelte
+<script>
+  // set once and no longer updated
+  const [popperRef, popperContent] = createPopperActions(initOptions);
+</script>
+
+<!-- will be merged with initOptions -->
+<div use:popperContent={dynamicOptions}/>
+```
+
 ### Accessing the Popper instance
 
 If access is needed to the raw [Popper instance](https://popper.js.org/docs/v2/constructors/#instance) created by the actions, you can reference the third element returned by `createPopperActions`. The third element is a function that will return the current Popper instance used by the actions.
@@ -78,3 +94,4 @@ Using the raw Popper instance to [manually recompute the popper's position](http
   }
 </script>
 ```
+

jest.config.js

@@ -1,6 +1,6 @@
 module.exports = {
   roots: [
-    './src',
+    '.',
   ],
   testMatch: [
     '**/__tests__/**/*.+(ts|js)',
@@ -9,5 +9,9 @@ module.exports = {
   transform: {
     '^.+\\.(ts)$': 'ts-jest',
   },
+  coveragePathIgnorePatterns: [
+    './node_modules/',
+    './tests/helpers.ts',
+  ],
 };
 

src/index.ts

@@ -50,13 +50,13 @@ export function createPopperActions<
     };
   };
 
-  const contentAction: ContentAction<TModifier> = (node, initOptions?) => {
+  const contentAction: ContentAction<TModifier> = (node, contentOptions?) => {
     contentNode = node;
-    options = initOptions;
+    options = { ...initOptions, ...contentOptions };
     initPopper();
     return {
-      update(newOptions: PopperOptions<TModifier>) {
-        options = newOptions;
+      update(newContentOptions: PopperOptions<TModifier>) {
+        options = { ...initOptions, ...newContentOptions };
         if (popperInstance && options) {
           popperInstance.setOptions(options);
         }

tests/helpers.ts

@@ -0,0 +1,24 @@
+/* eslint-disable @typescript-eslint/explicit-module-boundary-types */
+// eslint-disable-next-line @typescript-eslint/no-explicit-any
+export type Action = (node: HTMLElement, params?: any) => ActionLifecycleHandlers;
+export type ActionLifecycleHandlers = {
+  // eslint-disable-next-line @typescript-eslint/no-explicit-any
+  update?: (params: any) => void,
+  destroy? : () => void,
+}
+
+export const getElements = () => [
+  global.document.createElement('div'),
+  global.document.createElement('div'),
+];
+
+export const mountWithAction
+    // eslint-disable-next-line @typescript-eslint/no-explicit-any
+    = (node: HTMLElement, action: Action, params?: any) => action(node, params);
+
+export const unmount = (_: HTMLElement, lifecycle: ActionLifecycleHandlers) => {
+  if (lifecycle.destroy) {
+    lifecycle.destroy();
+  }
+};
+

tests/init.test.ts

@@ -0,0 +1,61 @@
+import { createPopperActions } from '../src/index';
+import { getElements, mountWithAction, unmount } from './helpers';
+
+test('instance should init if and only if ref and content is mounted', () => {
+  // Arrange
+  const [refDiv, contentDiv] = getElements();
+  const [refAction, contentAction, getInstance] = createPopperActions();
+
+  // Act and Assert
+  expect(getInstance()).toBeNull();
+  mountWithAction(refDiv, refAction);
+
+  expect(getInstance()).toBeNull();
+  mountWithAction(contentDiv, contentAction);
+
+  expect(getInstance()).not.toBeNull();
+});
+
+test('instance should deinit if ref is unmounted', () => {
+  // Arrange
+  const [refDiv, contentDiv] = getElements();
+  const [refAction, contentAction, getInstance] = createPopperActions();
+  mountWithAction(contentDiv, contentAction);
+  const refLifecycle = mountWithAction(refDiv, refAction);
+
+  // Act
+  unmount(refDiv, refLifecycle);
+
+  // Assert
+  expect(getInstance()).toBeNull();
+});
+
+test('instance should deinit if content is unmounted', () => {
+  // Arrange
+  const [refDiv, contentDiv] = getElements();
+  const [refAction, contentAction, getInstance] = createPopperActions();
+  mountWithAction(refDiv, refAction);
+  const contentLifecycle = mountWithAction(contentDiv, contentAction);
+
+  // Act
+  unmount(contentDiv, contentLifecycle);
+
+  // Assert
+  expect(getInstance()).toBeNull();
+});
+
+test('instance should deinit if ref and content is unmounted', () => {
+  // Arrange
+  const [refDiv, contentDiv] = getElements();
+  const [refAction, contentAction, getInstance] = createPopperActions();
+  const refLifecycle = mountWithAction(refDiv, refAction);
+  const contentLifecycle = mountWithAction(contentDiv, contentAction);
+
+  // Act
+  unmount(refDiv, refLifecycle);
+  unmount(contentDiv, contentLifecycle);
+
+  // Assert
+  expect(getInstance()).toBeNull();
+});
+