Add support for the spread operator to jshydra

[kzar]

Background

Since we already transpile a bunch of our JavaScript code, why not also add support for the ​spread operator?

What to change

Add support for the spread operator to jshydra. For example:

[1, ...[2, 3], 4];

  |
  v

[1].concat([2, 3]).concat([4]);

Math.max(...[1, 2]);

  |
  v

Math.max.apply(Math.max, [1, 2]);

foo(1, ...[2, 3], 4);

  |
  v

foo.apply(null, [1].concat([2, 3]).concat([4]));

[trev]

I've modified the examples to show how the code needs to be converted. The way I am setting the first parameter to apply() isn't entirely correct but should be good enough for us.

[sebastian]

jsHydra is no longer maintained, as we don't transpile the code anymore.