Typescript does not recognize function Boolean() as a check for undefined

I followed the submission guidelines.

I prefer to check for a defined object using Boolean(object) rather than !!object, which I consider bad style. Typescript linter recognizes !! as a check for undefined but does not recognize Boolean() as a check for undefined.

I could not find a tsconfig or tslint configuration setting related to this behavior.

2.9.0-dev.20180511 (typescript@next)

"Boolean" "Boolean(" "function Boolean"

Code
This is not production code but a simple demonstration only to satisfy the expression tree.

function booleanTest() {
    let value: Array<object> | undefined = undefined;

    if (Date.now() > 1) {
        value = [{}];
    }

    if (Boolean(value)) {
        console.log(value.length);
    }
}

Expected behavior:
No Typescript linter errors

Actual behavior:
Typescript linter in VS Code displays an error "[ts] Object is possibly 'undefined'." with a red squiggly on the final reference to variable "value".

Playground Link:

Start with the provided TypeScript example and investigate the type-checking path for control-flow narrowing through Boolean(value), comparing it with the recognized !!value form. Done means the example no longer reports that value may be undefined while preserving correct behavior for other Boolean calls.