Giters

salesforce / near-membrane

JavaScript Near Membrane Library that powers Lightning Locker Service

Geek Repo:Geek Repo

Github PK Tool:Github PK Tool

Is window.chrome problematic?

caridy opened this issue · comments

commented

@jfparadis raised this issue during the SES meeting today considering that window.chrome is not configurable.

commented 
Object.getOwnPropertyDescriptor(window, 'chrome')
{value: {…}, writable: true, enumerable: true, configurable: false}

This is not problematic because even though it is non-configurable, it is writable, therefore we can replace the value with undefined (in the case of SES), or with a Proxy in the case of our use-case.

/cc @erights @jdalton

commented

The issue I raised is a little different, and it's due to the fact that window.chrome can't be removed, which means that:

  • typeof chrome === 'undefined' fails
  • an accidental global can't be detected with a ReferenceError.

In addition, this global is unspecified API, and it's pure luck that it can be nullified. This is a great canari alerting to a problem...

The language specs should include an invariant to at least maintain status quo on the current non-configurable objects (better, make them configurable), but more importantly prevent other objects to appear as non-configurable or non-writable!