CODEWITHSUNDEEP
javascriptjavajava-8nashorn
richetyann
richetyann

Reputation: 46

Basic JS object {a:1,b:2} not supported in Nashorn?

I was a bit surprised when raising an exception with this simple expression in Nashorn (JDK8 from Oracle, latest) : 

ScriptEngineManager manager = new ScriptEngineManager();
engine = manager.getEngineByName("js");
engine.eval("{a:1,b:2}");

Which gives

javax.script.ScriptException: :1:6 Expected ; but found : {a:1,b:2}; ^ in at line number 1 at column number 6 at jdk.nashorn.api.scripting.NashornScriptEngine.throwAsScriptException(NashornScriptEngine.java:470) at jdk.nashorn.api.scripting.NashornScriptEngine.compileImpl(NashornScriptEngine.java:537) at jdk.nashorn.api.scripting.NashornScriptEngine.compileImpl(NashornScriptEngine.java:524) at jdk.nashorn.api.scripting.NashornScriptEngine.evalImpl(NashornScriptEngine.java:402) at jdk.nashorn.api.scripting.NashornScriptEngine.eval(NashornScriptEngine.java:155) at javax.script.AbstractScriptEngine.eval(AbstractScriptEngine.java:264)

Any idea ?

Upvotes: 2

Views: 303

Answers (2)

adiga
adiga

Reputation: 35232

Assuming this functionality is similar to javascript eval, you're getting this error because eval("{a:1,b:2}") evaluates {} as a code block and not as an object literal.

eval("{a:1,b:2}")

That code is equivalent to:

{
  a: 1,
  b: 2
}

The error is being thrown in the b: 2 line. Here, a becomes a labeled statement within a new {} block. So, if you had created an object literal with just one property, this would've worked.

eval("{a:1}") // no errors

If you want an object literal, then assign it to a variable

eval("var obj = {a:1,b:2}")
console.log(obj)

Upvotes: 2

richetyann
richetyann

Reputation: 46

Thanks to adiga, using 

ScriptEngineManager manager = new ScriptEngineManager();
engine = manager.getEngineByName("js");
engine.eval("({a:1,b:2})");

solved my problem. (Note the parenthesis which disable the "code block")

Upvotes: 0

Related Questions