Index: node_modules/d3-time/src/duration.js
===================================================================
--- node_modules/d3-time/src/duration.js	(revision e4c61dd6cd86e06265bc2bd91adba84a0f04044a)
+++ node_modules/d3-time/src/duration.js	(revision e4c61dd6cd86e06265bc2bd91adba84a0f04044a)
@@ -0,0 +1,7 @@
+export const durationSecond = 1000;
+export const durationMinute = durationSecond * 60;
+export const durationHour = durationMinute * 60;
+export const durationDay = durationHour * 24;
+export const durationWeek = durationDay * 7;
+export const durationMonth = durationDay * 30;
+export const durationYear = durationDay * 365;