(module

  (memory $memory 1)
  (export "memory" (memory $memory))

  (func (export "load_first_item_in_mem") (param $num i32) (result i32)
    i32.const 0

    ;; load first item in memory and return the result
    i32.load
  )

)
const url = '{%wasm-url%}';
await WebAssembly.instantiateStreaming(fetch(url)).then((result) => {
  const load_first_item_in_mem = result.instance.exports.load_first_item_in_mem;
  const memory = result.instance.exports.memory;

  const dataView = new DataView(memory.buffer);
  // Store 30 at the beginning of memory
  dataView.setUint32(0, 30, true);

  console.log(load_first_item_in_mem(100));
  // Expected output: 30
});

Wat Demo: load