typescript2.0 - tslint no-null-keyword and typescript's lib.d.ts with strict null checking -

i've been using tslint quite time no-null-keyword enabled. recently, i've upgraded typescript 2.0 , enabled --strictnullchecking. however, looking @ typescript's lib.d.ts, appears impossible keep no-null-keyword enabled (at first glance), since result of calls can null. example:

const result: regexpexecarray | null = regex.exec(regexstr);  if (result === null) { // <-- tslint complains check     throw new error("foo location: result of regex null."); }  // or // if (result !== null) { //     ...do  // } 

the question the-right-thing-to-do?

disable no-null-keyword tslint?

use hack (?):

const result: regexpexecarray = regex.exec(regexstr)!;  if (result == undefined) { // check if result undefined or null     throw new error("foo location: result of regex null."); } 

or else?

no-null-keyword lint rule. it's primary purpose prevent added complexity of using both undefined , null similar purpose.

but doesn't remove vendor codebase, , used in lot of libraries.

result == undefined indeed valid js idiom if need check null , undefined values. not considered hack (afaik) , lot preferable simple dangerous falsy checking: if (!result) {..}.

tslint allows exception === rule:

"triple-equals": [true, "allow-undefined-check"]