some code review

[lpatiny]

• this does not make sense in static functions
  

  spectra-data/src/range/Ranges.js

  Line 98 in f8100bd

  this.options = Object.assign({}, {

• could be renamed to toXY
  https://github.com/cheminfo-js/spectra-data/blob/f8100bd69498719fe0bd46267c1cb369c9e49611/src/range/peak2Vector.js

• It is important to always name the function to have it in the stack trace (other it is anonymous function). For example in:
  https://github.com/cheminfo-js/spectra-data/blob/9fec551/src/range/peak2Vector.js

module.exports = function toXY(peaks, opt) {

• if possible it would be nice not to have to support 2 format of peaks. Only x, y, width (or x,y, but not x,intensity)
  https://github.com/cheminfo-js/spectra-data/blob/f8100bd69498719fe0bd46267c1cb369c9e49611/src/range/peak2Vector.js

• For power of 2 it is likely that multiply * multiply is faster than Math.pow(xx,2)

• Is it really useful here ?
  https://github.com/cheminfo-js/spectra-data/blob/9fec551/src/range/utils.js

• What does this method and why > 11 ?
  https://github.com/cheminfo-js/spectra-data/blob/e921673/src/range/utils.js#L5
  Is is related to ACS formatting ? I guess then the number of decimals should be an option. For carbon we need only one decimal, for proton 2

• remove oldACS ?

• Don't use global variable for other things that constants
  

  spectra-data/src/range/acs/acs.js

  Lines 7 to 9 in e921673

  	var acsString = '';
  	var parenthesis = '';
  	var rangeForMultiplet = false;

• You are making a copy of ranges through JSON.parse / JSON.stringify and therefore there can not be any function on this object
  

  spectra-data/src/range/acs/acs.js

  Lines 14 to 20 in e921673

  	var ranges = JSON.parse(JSON.stringify(rangesIn));
  	if (ranges[0].delta1) {//Old signals format
  	return old.toACS(ranges, options);
  	}
  	if(ranges.update)
  	ranges = ranges.update();

• Would be better to have a hidden internal class for acsString (AcsStringBuilder) so that we can have an instance of it and call 'this' instead of using global variables