This issue is an enhancement request/tracking item pertaining to the TypeScript 2.0 definitions for D3 version 4 modules in the DefinitelyTyped/types-2.0 Branch.

The enhancement sought is the module-by-module vetting and updating of the definitions and related tests to ensure they perform with compiler option --strictNullChecks, i.e. determining the need for explicit union types with undefined, null or both. In some cases, this may require reviewing D3 source code, where the API docs are not explicit.

This is a follow-up open item carried over from the original collaborative development repo d3-v4-definitelytyped

Specifically, this issue is related to the Definition Request #9936 and the following references:

• d3-v4-definitelytyped PR 113 cc @jiemakel
• d3-v4-definitelytyped Issue 119 cc @timruffles

For tracking purposes, below is a checklist of the definitions, to be reviewed and updated as necessary:

• d3-array
• d3-axis
• d3-brush
• d3-chord
• d3-collection
• d3-color
• d3-contour
• d3-dispatch
• d3-drag
• d3-dsv
• d3-ease
• d3-force
• d3-format
• d3-geo
• d3-hierarchy
• d3-hsv
• d3-interpolate
• d3-path
• d3-polygon
• d3-quadtree
• d3-queue
• d3-random
• d3-request
• d3-sankey
• d3-scale
• d3-selection
• d3-selection-multi
• d3-shape
• d3-time
• d3-time-format
• d3-timer
• d3-transition
• d3-voronoi
• d3-zoom

PRs to support the completion of this effort are welcome!!! Please ensure the definition authors listed in the header comment are advised of proposed changes before a merge.

cc @gustavderdrache @Ledragon

Edit: missing link alias in repo link.
EDIT: Updated completed modules (2016-12-05)
EDIT: Updated completed modules (2016-12-07)
EDIT: Updated (2017-05-02) Added d3-sankey and d3-contour to tracking
EDIT: Updated completed modules (2017-05-13)
EDIT: Updated completed modules (2017-10-12)
EDIT: Updated completed modules (2017-11-04)