Is throws a reserved word in javascript?

The throw keyword[edit | edit source]

The throw keyword is used to be sure that an exception is caught when it occurs. It has the obligatory catch clause, and the optional finally clause. If the code inside the try block does not cause an exception, the code inside the finally block will execute, if it exists. If an error occurs, the comments inside the catch clause will execute, the finally block will execute, if it exists.

Table of Contents Show

The throw keyword[edit | edit source]
Examples[edit | edit source]
See also[edit | edit source]
What are Reserved Keywords?
Reserved Keywords in ECMAScript 5 (ES5)
Reserved Keywords in ECMAScript 6 (ES6)
Future Reserved Keywords in Older Standards
What are the reserved words in JavaScript?
Which is not a reserved word in JavaScript?
Is array a reserved word in JavaScript?
Is callback a reserved word in JavaScript?

Examples[edit | edit source]

The code

  var result;

  try {
    result = log(-12.05);
    alert("Executed comment successfully.");
  } catch(err) {
    document.getElementById("demo").innerHTML = err.message;
	throw("An error occurred, and result could not be calculated!");
  } finally {
    alert("result = " + result); // This line will execute anyway
  }

(An exception with the text "An error occurred, and result could not be calculated!" will be thrown.

result = undefined

What are Reserved Keywords?

JavaScript has a number of reserved keywords. These are the words that you cannot use as identifiers (variable names, function names, and loop labels) in your JavaScript programs.

Reserved Keywords in ECMAScript 5 (ES5)

The following list shows the keywords that are reserved in ECMAScript 5. It also includes keywords that are reserved for future as well as keywords that are disallowed in strict mode.

arguments sm break case catch class fr const fr continue debugger default delete do else enum fr eval sm export fr extends fr false finally for function if implements sm import fr in instanceof interface sm let sm new null package sm private sm protected sm public sm return static sm super fr switch this throw true try typeof var void while with yield sm

Note: The keywords arguments and eval are not strictly reserved keywords, but they are treated like keywords in strict mode, so they cannot be used as identifiers. Additionally, the keywords null, true, and false cannot be used as identifiers in ECMAScript.

Reserved Keywords in ECMAScript 6 (ES6)

The following list shows the keywords that are reserved in ECMAScript 6. It also includes keywords that are reserved for future as well as keywords that are disallowed in strict mode.

arguments sm await break case catch class const continue debugger default delete do else enum fr eval sm export extends false finally for function if implements sm import in instanceof interface sm let sm new null package sm private sm protected sm public sm return static sm super switch this throw true try typeof var void while with yield

Future Reserved Keywords in Older Standards

The following list shows the keywords that were reserved as future keywords by the older ECMAScript specifications (before ECMAScript 5 or ES5).

abstract boolean byte char double final float goto int long native short synchronized throws transient volatile

Note: For optimal backwards compatibility, you should better avoid using all the keywords shown on this page as variable names or property names in your JavaScript code.

What are the reserved words in JavaScript?

JavaScript Reserved Words.

Which is not a reserved word in JavaScript?

The NaN , Infinity , and undefined are not reserved keywords in JavaScript But you must avoid using them. They are properties of the global object and have special meanings. Although they are immutable & read-only properties, JavaScript does not throw any errors if you declare them in the global scope.

Is array a reserved word in JavaScript?

Some SPECIAL words such as Object , Array , Function , Method , Number etc are not belong to keywords in Javascrpt: Reserved Keywords in Javascript.

Is callback a reserved word in JavaScript?

For your top function, callback is the name of the third argument; it expects this to be a function, and it is provided when the method is called. It's not a language keyword - if you did a "find/replace all" of the word "callback" with "batmanvsuperman", it would still work.