Identify whether a variable is defined in the environment.
Because it doesn't return the value, this function is cheaper than get.
However, if you do need the value as well, you should just check the
return of get for null instead of using this function first.
// good usageif ("MY_ENV_FLAG"inenvironment)
doSomething();
// bad usageif ("MY_ENV_VAR"inenvironment)
doSomething(environment["MY_ENV_VAR"]);
// do this insteadif (autovar = environment.get("MY_ENV_VAR"))
doSomething(var);
Identify whether a variable is defined in the environment.
Because it doesn't return the value, this function is cheaper than get. However, if you do need the value as well, you should just check the return of get for null instead of using this function first.