Add IsEqual type

[doz13189]

Close #346

[sindresorhus]

https://github.com/sindresorhus/type-fest/pull/522/files#r1033002320 still needs to be done

[sindresorhus]

https://github.com/sindresorhus/type-fest/pull/522/files#r1033002320 still needs to be done

[doz13189]

https://github.com/sindresorhus/type-fest/pull/522/files#r1033002320 still needs to be done

Sorry, I misread.
401ad60

[trevorade]

FYI

There are two self-identity bugs that can pretty simply be fixed: TS Playground

Both of these evaluate to false:

IsEqual<{a: 1} & {a: 1}, {a: 1}>
IsEqual<{a: 1} | {a: 1}, {a: 1}>

The fix is to expand the check a touch:

type IsEqual<A, B> =
    (<G>() => G extends A & G | G ? 1 : 2) extends
    (<G>() => G extends B & G | G ? 1 : 2)
    ? true
    : false;

---

There's also this bug but I'm unaware of a fix: TS Playground

This evaluates to false:

IsEqual<{a: 1} & {b: 2}, {a: 1, b: 2}>

[sindresorhus]

@trevorade Would you mind moving this to an issue instead? Otherwise it will be forgotten.

[trevorade]

@trevorade Would you mind moving this to an issue instead? Otherwise it will be forgotten.

Created #537