d3-tip doesn't work with webpack

Question

I use webpack and TypeScript and it seems that d3-tip isn't able to work with webpack. I get error on mouseover events "Uncaught TypeError: Cannot read property 'target' of null".

This error occurs because d3.event in the d3-tip module is null.

I include modules as follows:

const d3: any = require("d3");
d3.tip = require("d3-tip");

but I guess that d3 there and d3 in the d3-tip module are different and this is the source of problems, but I don't know how to solve it. In the d3-tip module we have:

(function (root, factory) {
    if (typeof define === 'function' && define.amd) {
        // AMD. Register as an anonymous module with d3 as a dependency.
        define(['d3'], factory)
    } else if (typeof module === 'object' && module.exports) {
        // CommonJS
        var d3 = require('d3')
        module.exports = factory(d3)
    } else {
        // Browser global.
        root.d3.tip = factory(root.d3)
    }
}(this, function (d3) {
...

And it compiles by webpack into

function(module, exports, __webpack_require__) {

var __WEBPACK_AMD_DEFINE_FACTORY__, __WEBPACK_AMD_DEFINE_ARRAY__, __WEBPACK_AMD_DEFINE_RESULT__;// d3.tip
// Copyright (c) 2013 Justin Palmer
//
// Tooltips for d3.js SVG visualizations

(function (root, factory) {
    if (true) {
        // AMD. Register as an anonymous module with d3 as a dependency.
        !(__WEBPACK_AMD_DEFINE_ARRAY__ = [__webpack_require__(465)], __WEBPACK_AMD_DEFINE_FACTORY__ = (factory), __WEBPACK_AMD_DEFINE_RESULT__ = (typeof __WEBPACK_AMD_DEFINE_FACTORY__ === 'function' ? (__WEBPACK_AMD_DEFINE_FACTORY__.apply(exports, __WEBPACK_AMD_DEFINE_ARRAY__)) : __WEBPACK_AMD_DEFINE_FACTORY__), __WEBPACK_AMD_DEFINE_RESULT__ !== undefined && (module.exports = __WEBPACK_AMD_DEFINE_RESULT__))
    } else if (typeof module === 'object' && module.exports) {
        // CommonJS
        var d3 = require('d3')
        module.exports = factory(d3)
    } else {
        // Browser global.
        root.d3.tip = factory(root.d3)
    }
}(this, function (d3) {
...

and it's obvious that AMD is using. If I could get the factory of d3-tip I would solve that problem.

Answer 1

pass the target element as the last parameter to tip.show()

var tip = require("d3-tip");
var tooltip = tip().html(d => d.value);
vis.call(tooltip)

vis.append("rect")
    // ...
    .on("mouseover", function() {
        tooltip.show.apply(this, [...arguments, this]);
    });

and d3-tip will pick it up and use as target. From source:

if (args[args.length - 1] instanceof SVGElement) target = args.pop()

another way:

.on("mouseover", function(d) {
    tooltip.show(d, this);
});

Answer 2

I found the solution. As I think webpack produces many instances of each module when it's required. I've used single-module-instance-webpack-plugin and it's solved my problem.

You also just need to initialize d3 in the fisrt time somewhere, it should be file like vendor.ts where you include vendor libraries:

// D3 and third-party components
const d3: any = require("d3");
d3.tip = require("d3-tip");

For pure JS initialization would be easy.