'WeakMap' is undefined in Vue 2.7.11 and above (IE10 and under)

[gingerbenw]

Version

2.7.11

Reproduction link

github.com

Steps to reproduce

Open a Vue2 app using internet explorer 10 or below

What is expected?

App loads and 'Hello Vue!' is displayed

What is actually happening?

App does not load and 'WeakMap' is undefined is printed to the console

---

WeakMap is not supported in Internet Explorer 10 or less and was introduced to Vue in version 2.7.11

[posva]

as a workaround, use a weakmap polyfill: https://github.com/polygonplanet/weakmap-polyfill

[gingerbenw]

Thanks @posva - we provide a framework to customers with a fairly wide browser base, while we're happy to include this polyfill for our own testing purposes, this does seem like a change in browser support that some of our customers may also be feeling. Does the Vue team intend to continue supporting these legacy browsers for Vue2, or is there an intended change in browser support that we should be prepared for?