To align with other implementations common in the community, but also to be more functionally correct, the two objects being compared now must have equal constructors.

`Map` / `Set` comparisons no longer support IE11

In previous verisons, .forEach() was used to ensure that support for Symbol was not required, as IE11 did not have Symbol and therefore both Map and Set did not have iterator-based methods such as .values() or .entries(). Since IE11 is no longer a supported browser, and support for those methods is present in all browsers and Node for quite a while, the comparison has moved to use these methods. This results in a ~20% performance increase.

`createCustomEqual` contract has changed

To better facilitate strict comparisons, but also to allow for meta use separate from caching, the contract for createCustomEqual has changed. See the README documentation for more details, but froma high-level:

meta is no longer passed through to equality comparators, but rather a general state object which contains meta
cache now also lives on the state object, which allows for use of the meta property separate from but in parallel with the circular cache
equals is now on state, which prevents the need to pass through the separate isEqual method for the equality comparator

`createCustomCircularEqual` has been removed

You can create a custom circular equality comparator through createCustomEqual now by providing circular: true to the options.

Custom `meta` values are no longer passed at callsite

To use meta properties for comparisons, they must be returned in a createState method.

Deep links have changed

If you were deep-linking into a specific asset type (ESM / CJS / UMD), they have changed location.

NOTE: You may no longer need to deep-link, as the build resolution has improved.

Enhancements

New "strict" comparators available

The following new comparators are available:

strictDeepEqual
strictShallowEqual
strictCircularDeepEqual
strictCircularShallowEqual

This will perform the same comparisons as their non-strict counterparts, but will verify additional properties (non-enumerable properties on objects, keyed objects on Array / Map / Set) and that the descriptors for the properties align.

`TypedArray` support

Support for comparing all typed array values is now supported, and you can provide a custom comparator via the new areTypedArraysEqual option in the createCustomEqual configuration.

Better build system resolution

The library now leverages the exports property in the package.json to provide builds specific to your method of consumption (ESM / CommonJS / UMD). There is still a minified UMD version available if you want to use it instead.