Kata

JS version update

There are no tests with functions as prototype. So solutions which just check that typeof proto === 'object' pass.

In the Information section, I think, there is some confusion between literals and primitives. A String literal like 'abc' is a primitive, and cannot be passed to Object.create(). But this is also true of any string variable, i.e. any variable whose typeof returns 'string': let str = String(); is also a string primitive and similarly cannot be used as a Prototype, despite the absence of a string literal in its definition.

To access inner [[Prototype]] property of object use its __proto__ property

In modern JavaScript, __proto__ is deprecated, and programmers are encouraged to use Object.set/getPrototypeOf() instead

This kata doesn't work with Node v10.x. Everything is either null or undefined.

This note in the kata description is incorrect:

But NaN, Infinity, /regular expression literals/, function(){} — they all are actually objects.

NaN and Infinity are numbers and therefore primitive values. They cannot be passed as the prototype into the native Object.create().

Approved

I also fixed a test case where it would fail on Node 6 + Babel version.

Trying to submit the code throws "Object # has no method 'log'" error.

When submitting my solution I get the error below. I have tested the solution in jsfiddle and it worked fine. Any ideas what's wrong?

 /runner/frameworks/javascript/cw-2.js:264 console.log("" + this.format(_message(Test.trace(ex))
 ^ TypeError: Object # has no method 'log' 
 at (/runner/frameworks/javascript/cw-2.js:264:25) 
 at Object.Test.handleError (/runner/frameworks/javascript/cw-2.js:254:26) 
 at [eval]:3:6 
 at Object. ([eval]-wrapper:6:22)
 at 
 at evalScript (node.js:536:25) 
 at startup (node.js:80:7) 
 at node.js:906:3      
 
 
 
 

 
 
 
     
     

default tests are confusing

1. One of predefined tests is not correct - it will always throw an exeption, because citizen is an object, but instanceof is working with functions:

Test.expect(veteran instanceof citizen, "veteran must inherit citizen");

2. I don't think that ask developers to use proto field is a good idea. Without native Object.create(null) there is no way (that will work in all browsers) to create an object with [[prototype]] === null.

In the example test fixture, what you currently have (as follows) is invalid code:

var veteran = Object.create(citizen, {panic: function(){
  return "SNAFU";
});

Try:

var veteran = Object.create(citizen, {panic: function(){
  return "SNAFU";
}});

Hrm... it works fine. But you pretty much told us exactly how to implement it. Almost line-by-line. Kinda takes all the fun and challenge out of it, I feel.

If anybody used a code snippet from the kata's description and had troubles with passing tests based on it — my big apologies!! There was a stupid bug, my fault. It could confuse warriors because gave wrong results, when the solution is actually ok. I've updated it and now it's ok! I'm the evil, undoubtedly! ]:-> And my big thanks to trymedo and westvud for discovering that thing! Well done guys! :)

This is my first kata, so there could be some unexploded ordnance in the kata. Any feedback is welcome :)