Approve ES2017 Array.includes()

[zeptonaut]

ES 2017 introduces an Array/String.includes() method that allows you to write:

if ('text1234'.includes('xt12')) {
  ...
}

instead of

if ('text1234'.indexOf('xt12') !== -1) {
  ...
}

This new syntax has already slipped into the codebase without causing any problems. Are there any objections to marking it as approved?

@eakuefner @benshayden

[zeptonaut]

Also relevant: the feature is widely implemented (Chrome 47, Firefox 43, Edge 14, Opera 34, Safari 9).

[benshayden]

sgtm, thanks!

(Looks like the link is for indexOf, not includes)

[lpy]

LGTM.
BTW, I guess we really shouldn't post any corp link publicly.

[zeptonaut]

@lpy This is definitely the policy. I'm going to start a conversation about this in an internal email thread to figure out how we should handle this wrt. code search, code review, etc.