fromEnvironment broken when compiling to javascript about sdk

[lrhn]

That's working as intended.

The String.fromEnvironment constructor accesses the compilation environment. When compiled for the web, it must be used with const to get its value while compiling, because the compilation environment is not available at runtime. The VM JIT compiler can use String.fromEnvironment without const because it runs directly from source and has access to the compiler options.

From the documentation:

This constructor is only guaranteed to work when invoked as const. It may work as a non-constant invocation on some platforms which have access to compiler options at run-time, but most ahead-of-time compiled platforms will not have this information.

The runtime UnsupportedError is reporting that calling without new is not supported.