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Firing Events

Most projects have a few use cases for fireEvent, but the majority of the time you should probably use @testing-library/user-event.

fireEvent

fireEvent(node: HTMLElement, event: Event)

Fire DOM events.

// <button>Submit</button>
fireEvent(
  getByText(container, 'Submit'),
  new MouseEvent('click', {
    bubbles: true,
    cancelable: true,
  })
)

fireEvent[eventName]

fireEvent[eventName](node: HTMLElement, eventProperties: Object)

Convenience methods for firing DOM events. Check out src/event-map.js for a full list as well as default eventProperties.

// <button>Submit</button>
const rightClick = { button: 2 }
fireEvent.click(getByText('Submit'), rightClick)
// default `button` property for click events is set to `0` which is a left click.

target: When an event is dispatched on an element, the event has the subjected element on a property called target. As a convenience, if you provide a target property in the eventProperties (second argument), then those properties will be assigned to the node which is receiving the event.

This is particularly useful for a change event:

fireEvent.change(getByLabelText(/username/i), { target: { value: 'a' } })

// note: attempting to manually set the files property of an HTMLInputElement
// results in an error as the files property is read-only.
// this feature works around that by using Object.defineProperty.
fireEvent.change(getByLabelText(/picture/i), {
  target: {
    files: [new File(['(⌐□_□)'], 'chucknorris.png', { type: 'image/png' })],
  },
})

dataTransfer: Drag events have a dataTransfer property that contains data transferred during the operation. As a convenience, if you provide a dataTransfer property in the eventProperties (second argument), then those properties will be added to the event.

This should predominantly be used for testing drag and drop interactions.

fireEvent.drop(getByLabelText(/drop files here/i), {
  dataTransfer: {
    files: [new File(['(⌐□_□)'], 'chucknorris.png', { type: 'image/png' })],
  },
})

Keyboard events: There are three event types related to keyboard input - keyPress, keyDown, and keyUp. When firing these you need to reference an element in the DOM and the key you want to fire.

fireEvent.keyDown(domNode, { key: 'Enter', code: 'Enter' })

fireEvent.keyDown(domNode, { key: 'A', code: 'KeyA' })

You can find out which key code to use at https://keycode.info/.

createEvent[eventName]

createEvent[eventName](node: HTMLElement, eventProperties: Object)

Convenience methods for creating DOM events that can then be fired by fireEvent, allowing you to have a reference to the event created: this might be useful if you need to access event properties that cannot be initiated programmatically (such as timeStamp).

const myEvent = createEvent.click(node, { button: 2 })
fireEvent(node, myEvent)
// myEvent.timeStamp can be accessed just like any other properties from myEvent

You can also create generic events:

// simulate the 'input' event on a file input
fireEvent(
  input,
  createEvent('input', input, {
    target: { files: inputFiles },
    ...init,
  })
)