code: function parseSpeed(value)
  {
      if(value in speeds)
      {
          value = speeds[value];
      }
  
      value = parseFloat(value);
      if(isNaN(value) || !value || value <= 0)
      {
          value = 1;
      }
      return value;
  }
docs: accept a speed name shortcuts or a number and give back an acceptable positive value.
  Fallback to 1 if value is out of valid range
  
  @param {string|number} value
  @returns {number}