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    noUnusedParameters

    An argument nobody uses

    Reports parameters that are declared and never read, with a leading underscore as the documented way to say you meant it.

    Since
    TypeScript 2.0
    strict
    Not in strict
    In your tsconfig
    "noUnusedParameters": true

    The same snippet both times. Only the option changed.

    With it off

    "noUnusedParameters": false
    export function greet(name: string, title: string) {
  return name
}

    Compiles clean

    With it on

    "noUnusedParameters": true
    export function greet(name: string, title: string) {
  return name
}

    Emits TS6133

    Why the compiler bothers

    Unlike an unused local, an unused parameter is often correct — a callback whose signature is fixed by whoever calls it does not get to drop the arguments it ignores. That is why the underscore convention is part of the rule rather than a workaround: `_event` is not silenced by a comment or a disable directive, it is silenced by saying what you mean in the name, which survives a rename and reads correctly to the next person.

    Takeaway

    Prefix with `_` rather than reaching for a disable comment.

    Where to go next

    22 options