laughinghan

• any: magic, ill-behaved type that acts like a combination of never (the proper [bottom type]) and unknown (the proper [top type])
  • Anything except never is assignable to any, and any is assignable to anything at all.
  • Identities: any & AnyTypeExpression = any, any | AnyTypeExpression = any
  • Key TypeScript feature that allows for [gradual typing].
• unknown: proper, well-behaved [top type]
  • Anything at all is assignable to unknown. unknown is only assignable to itself (unknown) and any.
  • Identities: unknown & AnyTypeExpression = AnyTypeExpression, unknown | AnyTypeExpression = unknown

• Prefer over any whenever possible. Anywhere in well-typed code you're tempted to use any, you probably want unknown.