Rust imports in wasm-pack code causing JS error

Question

I'm getting a JS error: Uncaught (in promise) TypeError: WebAssembly.instantiate(): Import #0 module="env" error: module is not an object or function

When I view the wasm file in the Chrome dev tools, I see import statements like this, at the top:

(module
  (func $blst_hash_to_g2 (;0;) (import "env" "blst_hash_to_g2") (param i32 i32 i32 i32 i32 i32 i32))
  (func $blst_sign_pk2_in_g1 (;1;) (import "env" "blst_sign_pk2_in_g1") (param i32 i32 i32 i32))
  (func $blst_scalar_from_bendian (;2;) (import "env" "blst_scalar_from_bendian") (param i32 i32))
  (func $blst_sk_check (;3;) (import "env" "blst_sk_check") (param i32) (result i32))

What is causing these import statements? How can I remove or fix them? I can see they are part of the blst Rust package, which is included by the blsttc package. The blst package uses bindgen to generate FFI bindings to blst.h, so maybe that has something to do with it?

This Github repo has the code. I am building using wasm-pack build --target=web

Answer 1

I fixed this by switching to Ubuntu 20.04 with latest everything and it works great now. I was on mac os 10.15.7.