@types/d3-hexbin and @types/d3 coexistence as global libraries

[hugoferreira]

• I tried using the @types/d3-hexbin package and had problems.
• I tried using the latest stable version of tsc. https://www.npmjs.com/package/typescript
• I have a question that is ignored in StackOverflow (Please ask any appropriate questions there).
• Mention the authors (see Definitions by: in index.d.ts) so they can respond.
  • Authors: @uncovertruth, @tomwanzek

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So, I'm using d3 and d3-hexbin as global libraries:

<script src="https://d3js.org/d3.v4.min.js"></script>
<script src="https://d3js.org/d3-hexbin.v0.2.min.js"></script>

... and referencing them in .ts as:

/// <reference types="d3" />
/// <reference types="d3-hexbin" />

However, although this works:

const svg = d3.select('#hitmap')

... this:

const hexbin = d3.hexbin()

... fails with a :

Property 'hexbin' does not exist on type 
  'typeof "/Users/bytter/node_modules/@types/d3/index"'

By looking at the tests, I can see that:

import * as d3Hexbin from 'd3-hexbin';

Would export the hexbin() function directly into the d3Hexbin namespace, but I'm unable to figure out how to conciliate this with d3-hexbin as a global library.

[tomwanzek]

Unfortunately, you are running into a known limitation of the TypeScript compiler.

When creating a TS definition file which is meant to export a global, one adds a line such as:

export as namespace d3;

In the definitions for D3, this line is added to the definition file that re-exports all the constituent modules of the "standard" bundle.

As a matter of TS compiler design, this statement can only be added once. Adding it a second time, e.g. in d3-hexbin, because D3 convention is to export into the same d3 global, will create a TS compiler error duplicate variable declaration. There is a lengthy discussion of this known issue in the DefinitelyTyped and TypeScript repos. See here and most importantly microsoft/TypeScript#9681.

Workaround:

So, I am afraid, the only suggestion I can make, is to write and use a custom definition file in your project which re-exports the D3 modules you require similar to the current D3 bundle definitions file and includes

export * from 'd3-hexbin';

Then you have only one d3 global which exposes the functionality you require.

[tomwanzek]

@hugoferreira Just checking in to see what the status of the issue is on your side?

[tomwanzek]

@hugoferreira Any update from your side? Can this issue be closed given the TS limitations/workaround outlined above, or do you require further issues management? Cheers, T

[tomwanzek]

Is this still an issue or can it be closed? Thx for a status confirmation.

[tomwanzek]

@andy-ms As a matter of maintaining open issues, could you kindly close this issue? There has been no update despite several inquiries. Thx in advance.

@hugoferreira Feel free to provide any new status/information to trigger a re-opening.