Why is crypto.subtle.digest designed to return a promise?

Every other system I’ve ever worked with has the signature hash(bytes) => bytes, yet whatever committee designed the Subtle Crypto API decided that the browser version should return a promise. Why? I’ve looked around but I’ve never found any discussion on the motivation behind that.

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    6 months ago

    It executes on a native thread in the background. That way it doesn’t stall the Javascript execution loop, even if you give it a gigabyte of data to hash.