feat: add useMountEffect

Author: jquense

src/useMountEffect.ts

@@ -0,0 +1,24 @@
+import { useEffect, EffectCallback } from 'react'
+
+/**
+ * Run's an effect on mount, and is cleaned up on unmount. Generally
+ * useful for interop with non-react plugins or components
+ *
+ * ```ts
+ *  useMountEffect(() => {
+ *    const plugin = $.myPlugin(ref.current)
+ *
+ *    return () => {
+ *      plugin.destroy()
+ *    }
+ *  })
+ * ```
+ * @param effect An effect to run on mount
+ *
+ *  @category effects
+ */
+function useMountEffect(effect: EffectCallback) {
+  return useEffect(effect, [])
+}
+
+export default useMountEffect

test/useMountEffect.test.tsx

@@ -0,0 +1,30 @@
+import useMountEffect from '../src/useMountEffect'
+import { renderHook } from './helpers'
+
+describe('useMountEffect', () => {
+  it('should run update only on mount', () => {
+    const teardown = jest.fn()
+    const spy = jest.fn(() => teardown)
+
+    const [, wrapper] = renderHook(
+      () => {
+        useMountEffect(spy)
+      },
+      { value: 1, other: false },
+    )
+
+    expect(spy).toHaveBeenCalledTimes(1)
+
+    wrapper.setProps({ value: 2 })
+
+    expect(spy).toHaveBeenCalledTimes(1)
+
+    wrapper.setProps({ value: 2, other: true })
+
+    expect(spy).toHaveBeenCalledTimes(1)
+
+    wrapper.unmount()
+
+    expect(teardown).toHaveBeenCalledTimes(1)
+  })
+})