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javascripttyped-arraysuint8array

Why do TypedArrays have a static length property with value 3

I just came across this gem when looking up some Uint8Array properties:

TypedArray.length

    Length property whose value is 3.

I tried it and it is true!

wtf

What? Why does this exist?!

Solution

  • For functions, the length property is how many parameters are in its argument list. For the Uint8Array constructor, that number is 3.

    function example2 (a, b) {}
function example3 (a, b, c) {}

console.log(example2.length);
console.log(example3.length);

    Regardless of the length property, any function can be passed any number of arguments, and the function can use or ignore all of them. So the length is just a hint about how many are likely to be used.

    // This function doesn't list any arguments, so it's length is 0
function example () {
  // ...but it uses 2 anyway.
  console.log(arguments[0], arguments[1])
}
console.log(example.length);
// .. and i can pass in more than 2, useless though it is.
example('first', 'second', 'third');