JavaScript: `repeat` can create an Array with wrong size

[Mingun]

This KSY when used without providing argument to the parameter (as WebIDE does) produces a value with value of [undefined], because the first Array constructor will be used (that accept elements):

meta:
  id: js_array_bug
params:
  - id: param
    type: u4
seq:
  - id: value
    size: 2
    repeat: expr
    repeat-expr: param

Generated code looks like

  Contexts.prototype._read = function() {
    this.value = new Array(this.param);
    for (var i = 0; i < this.param; i++) {
      this.value[i] = this._io.readBytes(2);
    }
  }

and because this.param is undefined it creates an array with one undefined element. Then i < undefined evaluated to false and we get an [undefined] in the value.

To eliminate this problem it is possible use the conversion to integer trick: this.param|0