JavaScript Promise Integration (JSPI) is a Phase 4 (Standardize the Feature) WebAssembly proposal for running asynchronous Web APIs alongside synchronous code.
JSPI is supported under the following browsers/engines through enabling a feature flag:
Chrome: chrome://flags/#enable-experimental-webassembly-jspi
Firefox: javascript.options.wasm_js_promise_integration
Node.js: --experimental-wasm-jspi