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##  ##  ##      ##  ##  ## ##   #   #   #   #   #  ##
#####   ####    #####   #   #   #   #   #   #   #  ####
##  #   ##      ##      ## ##    # #    #    # #   ##
##   #  ######  ##       ###      #    ###    #    ######

$ curl repovive.com/roadmaps/javascript/introduction-to-typescript/the-unknown-type

░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░███████████████████████████████████████████████████████████████████████████████████

#####   ######  #####    ###    #   #  ###  #   #  ######
##  ##  ##      ##  ##  ## ##   #   #   #   #   #  ##
#####   ####    #####   #   #   #   #   #   #   #  ####
##  #   ##      ##      ## ##    # #    #    # #   ##
##   #  ######  ##       ###      #    ###    #    ######

$ curl repovive.com/roadmaps/javascript/introduction-to-typescript/the-unknown-type

Repovive

The unknown Type - Introduction to TypeScript | JavaScript | Repovive

Repovive.

JavaScript22 sections · 783 units18h total

Open in Course

The unknown Type

Safer alternative to any

unknown is a type-safe version of any. You must narrow it before use.

let value: unknown = getExternalData();

// Error: can't use unknown directly
value.toString();

// OK: narrowed with type check
if (typeof value === "string") {
  console.log(value.toUpperCase());
}

Use unknown for data from external sources.