constructor(allowAbbreviation, maxAbbreviationError, fixedDigits, itemSeparator) {
        this.allowAbbreviation = allowAbbreviation;
        this.maxAbbreviationError = maxAbbreviationError;
        this.fixedDigits = fixedDigits;
        this.itemSeparator = itemSeparator;
    }
@param {!boolean} allowAbbreviation
@param {!number} maxAbbreviationError
@param {int|undefined} fixedDigits
@param {!string} itemSeparator

@property {!boolean} allowAbbreviation Should outputs be shortened, if possible?
@property {!number} maxAbbreviationError How much error is abbreviating allowed to introduce?
@property {int|undefined} fixedDigits Use toFixed? How many digits?
@property {!string} itemSeparator What should list items be separated by?