v3.4.0

Aligns polyfill with spec changes.

Initial value of lastReportedSize changed from 0, 0 to -1, -1 allowing for consistent notifications to be triggered when an element is observed for the first time.

const el = document.createElement('div');
const ro = new ResizeObserver(() => { ... });
ro.observe(el); // Will now notify with size `0, 0`.

w3c/csswg-drafts#3664 (comment)

v4.0.0-4

• Removes memory leak potential
• Adds back capture phase for events

v4.0.0-3

• Improves event detection in nested documents
• Adds export map

v4.0.0-2

• Rollup both ESM and UMD bundles

v4.0.0-1

• Initial support for Shadow DOM and other documents
• Add touch events
• Fixes UMD build - Thanks @trusktr!

v3.3.1

• Fixes an issue where isElement sometimes returns false on elements within an iFrame. Thanks @JayaKrishnaNamburu!

v3.3.0

• Reports readonly ResizeObserverSize[] to the observer callback
• Exposes ResizeObserverSize

v3.2.0

• Fixes issue where calling disconnect would prevent the observer from being used to observe again (#104).
• Uses time instead of frame counts to capture certain events.
• Replaces Map with WeakMap

v3.1.3

• Fixes issue with older versions of chromium.
  No notifications were fired due to differences in MutationObserver implementation.

Tested:
Chromium 45.0.2454.0 (64-bit)

v3.1.2

• Add missing device-pixel-content-box option to readme.