Suggestion: a built-in TypedArray interface

I would have expected a TypedArray interface to exist in
the built-in declaration libraries. Instead, there are independent types for
Int8Array, etc, with no common base type.

interface Int8Array { /* ... */ }
interface Int8ArrayConstructor { /* ... */ }
declare const Int8Array: Int8ArrayConstructor;

interface Uint8Array { /* ... */ }
interface Uint8ArrayConstructor { /* ... */ }
declare const Uint8Array: Uint8ArrayConstructor;

// ...

It seems sensible that there should be a common TypedArray type, both because

• a TypeScript user might want to declare a variable as a TypedArray, and
• it would reduce repetition in the built-in declaration files

interface TypedArray { /* ... */ }

interface Int8Array extends TypedArray { }
interface Int8ArrayConstructor { /* ... */ }
declare const Int8Array: Int8ArrayConstructor;

interface Uint8Array extends TypedArray { }
interface Uint8ArrayConstructor { /* ... */ }
declare const Uint8Array: Uint8ArrayConstructor;

// ...

Is there a good reason why there is no TypedArray type? If not, I can submit a PR.

Use case

Consider the isTypedArray() function from lodash.
Currently, it is declared as follows:

function isTypedArray(value: any): boolean;

This proposal would enable an appropriate type-guard, without declaring
a convoluted union type:

function isTypedArray(value: any): value is TypedArray;

Start with the built-in declarations in src/lib/es5.d.ts, especially the Int8Array definition linked in the issue, and compare the other typed-array declarations. Check the ECMAScript TypedArray reference and the lodash isTypedArray use case; done means a common TypedArray type is available and the typed-array declarations can use it without losing their specific types.