Using Atomics.waitAsync in js code compiled by Closure compiler was giving an error.

// source.js
function b(a) {
  return Atomics.waitAsync(a, 1, 2);
}
b(new Int32Array(10));

# compile command 
> java -jar node_modules/google-closure-compiler-java/compiler.jar --js source.js --compilation_level ADVANCED
source.js:2:17: WARNING - [JSC_INEXISTENT_PROPERTY] Property waitAsync never defined on Atomics
  2|   return Atomics.waitAsync(a, 1, 2);
                      ^^^^^^^^^

0 error(s), 1 warning(s), 72.7% typed
var a=new Int32Array(10);Atomics.g(a,1,2);

There are two issues here

• JSC_INEXISTENT_PROPERTY error
• the waitAsync method is renamed to g

By adding an extern file Async.js to the compilation both problems are resolved

// Async.js
/** @externs */

/**
 * @param {Int32Array|BigInt64Array} typedArray
 * @param {number} index
 * @param {number} value
 * @param {number=} timeout
 * return {!{async: boolean, value: string|!Promise<!string>}}
 */
Atomics.waitAsync = function(typedArray, index, value, timeout){};

# compile with extern file
❯ java -jar node_modules/google-closure-compiler-java/compiler.jar --js source.js Atomics.js --compilation_level ADVANCED
var a=new Int32Array(10);Atomics.waitAsync(a,1,2);