targets/wasm_exec: add runtime.getRandomData to gojs imports

Author: pedramktb

targets/wasm_exec.js

@@ -294,6 +294,15 @@
 						return BigInt((timeOrigin + performance.now()) * 1e6);
 					},
 
+					// func getRandomData(r []byte)
+					"runtime.getRandomData": (slice_ptr, slice_len, slice_cap) => {
+						const buf = loadSlice(slice_ptr, slice_len, slice_cap);
+						// crypto.getRandomValues has a 65536-byte limit per call
+						for (let offset = 0; offset < buf.length; offset += 65536) {
+							crypto.getRandomValues(buf.subarray(offset, Math.min(offset + 65536, buf.length)));
+						}
+					},
+
 					// func sleepTicks(timeout int64)
 					"runtime.sleepTicks": (timeout) => {
 						// Do not sleep, only reactivate scheduler after the given timeout.