(module
  (func (export "select_simple") (result i32)
    ;; load two values onto the stack
    i32.const 10
    i32.const 20

    ;; change to `1` (true) to get the first value (`10`)
    i32.const 0
    select
  )
  (func (export "select_externref") (param $value externref) (param $condition i32) (result externref)
    ;; this is "select t", the explicitly typed variant
    ref.null extern
    local.get $value
    local.get $condition
    select (result externref)
  )
)

var url = "{%wasm-url%}";
await WebAssembly.instantiateStreaming(
  fetch(url)
).then(result => {
  const { select_simple, select_externref } = result.instance.exports;

  console.log(select_simple());

  // if the second parameter is zero, returns the first paramater (which may be an arbitrary JS value)
  const map = new Map();
  console.log(select_externref(map, 0)); // logs Map {}
  console.log(select_externref(map, -1)); // logs null
});