How to use the d3-time-format.isoFormat function in d3-time-format

// Test Formating and Parsing
// ----------------------------------------------------------------------

// local time -----------------------------------------------------------

formatFn = d3TimeFormat.timeFormat('.%L');
parseFn = d3TimeFormat.timeParse('.%L');

// utc ------------------------------------------------------------------

formatFn = d3TimeFormat.utcFormat('.%L');
parseFn = d3TimeFormat.utcParse('.%L');

// iso ------------------------------------------------------------------

let dateString: string = d3TimeFormat.isoFormat(new Date(2016, 6, 6));
let date: Date = d3TimeFormat.isoParse('2016-07-08T14:06:41.386Z');

// ----------------------------------------------------------------------
// Test Locale Definition
// ----------------------------------------------------------------------

let dateTimeSpecifier: string = localeDef.dateTime;
let dateSpecifier: string = localeDef.date;
let timeSpecifier: string = localeDef.time;
let periods: [string, string] = localeDef.periods;
let days: [string, string, string, string, string, string, string] = localeDef.days;
let shortDays: [string, string, string, string, string, string, string] = localeDef.shortDays;
let months: [string, string, string, string, string, string, string, string, string, string, string, string] = localeDef.months;
let shortMonths: [string, string, string, string, string, string, string, string, string, string, string, string] = localeDef.shortMonths;

localeDef = {

// Test Formating and Parsing
// ----------------------------------------------------------------------

// local time -----------------------------------------------------------

formatFn = d3TimeFormat.timeFormat('.%L');
parseFn = d3TimeFormat.timeParse('.%L');

// utc ------------------------------------------------------------------

formatFn = d3TimeFormat.utcFormat('.%L');
parseFn = d3TimeFormat.utcParse('.%L');

// iso ------------------------------------------------------------------

let dateString: string = d3TimeFormat.isoFormat(new Date(2016, 6, 6));
let date: Date = d3TimeFormat.isoParse('2016-07-08T14:06:41.386Z');

// ----------------------------------------------------------------------
// Test Locale Definition
// ----------------------------------------------------------------------

let dateTimeSpecifier: string = localeDef.dateTime;
let dateSpecifier: string = localeDef.date;
let timeSpecifier: string = localeDef.time;
let periods: [string, string] = localeDef.periods;
let days: [string, string, string, string, string, string, string] = localeDef.days;
let shortDays: [string, string, string, string, string, string, string] = localeDef.shortDays;
let months: [string, string, string, string, string, string, string, string, string, string, string, string] = localeDef.months;
let shortMonths: [string, string, string, string, string, string, string, string, string, string, string, string] = localeDef.shortMonths;

localeDef = {