README.md

d3-require

A minimal, promise-based implementation to require asynchronous module definitions (AMD). This implementation is small and supports a strict subset of AMD. It is designed to work with browser-targeting libraries that implement one of the recommended UMD patterns. The constraints of this implementation are:

• The define method must be called synchronously by the library on load.

• Only the built-in exports and module dependencies are allowed; no require as in CommonJS. The module entry only contains an exports property.

• Named module definitions (e.g., jQuery) are treated as anonymous modules.

By default, d3.require loads modules from jsDelivr; the module name can be any package (or scoped package) name optionally followed by the at sign (@) and a semver range. For example, d3.require("d3@5") loads the highest version of D3 5.x. Relative paths and absolute URLs are also supported. You can change this behavior using d3.requireFrom.

Installing

If you use NPM, npm install d3-require. Otherwise, download the latest release. You can also load directly from jsDelivr. AMD, CommonJS, and vanilla environments are supported. In vanilla, d3 and define globals are exported:

<script src="https://cdn.jsdelivr.net/npm/d3-require@1"></script>
<script>

d3.require("d3-array").then(d3 => {
  console.log(d3.range(100));
});

</script>

API Reference

# d3.require(names…) <>

To load a module:

d3.require("d3-array").then(d3 => {
  console.log(d3.range(100));
});

To load a module within a version range:

d3.require("d3-array@1").then(d3 => {
  console.log(d3.range(100));
});

To load two modules and merge them into a single object:

d3.require("d3-array", "d3-color").then(d3 => {
  console.log(d3.range(360).map(h => d3.hsl(h, 1, 0.5)));
});

Note: if more than one name is specified, the promise will yield a new object with each of the loaded module’s own enumerable property values copied into the new object. If multiple modules define the same property name, the value from the latest module that defines the property is used; it is recommended that you only combine modules that avoid naming conflicts.

If a module’s property value is null or undefined on load, such as d3.event, the value will be exposed via getter rather than copied; this is to simulate ES module-style live bindings. However, property values that are neither null nor undefined on load are copied by value assignment, and thus are not live bindings!

# d3.requireFrom(resolver) <>

Returns a new require function which loads modules from the specified resolver, which is a function that takes a module name and returns the corresponding URL. For example:

const myRequire = d3.requireFrom(async name => {
  return `https://unpkg.com/${name}`;
});

myRequire("d3-array").then(d3 => {
  console.log(d3.range(100));
});

The returned require function exposes the passed in resolver as require.resolve. See also resolveFrom.

# require.resolve(name[, base]) <>

Returns a promise to the URL to load the module with the specified name. The name may also be specified as a relative path, in which case it is resolved relative to the specified base URL. If base is not specified, it defaults to the global location.

# require.alias(aliases) <>

Returns a require function with the specified aliases. For each key in the specified aliases object, any require of that key is substituted with the corresponding value. The values can be strings representing the name or URL of the module to load, or a literal non-string value for direct substitution. For example, if React and ReactDOM are already in-scope, you can say:

const myRequire = d3.require.alias({
  "react": React,
  "react-dom": ReactDOM
});

myRequire("semiotic").then(Semiotic => {
  console.log(Semiotic);
});

# d3.resolveFrom(origin, mains) <>

Returns a new resolver function which loads modules from the specified origin and observes the specified mains entry points. The returned function can be passed to requireFrom. For example:

const myResolve = d3.resolveFrom(`https://unpkg.com/${name}`);
const myRequire = d3.requireFrom(myResolve);

# d3.RequireError

The class of error that may be thrown by require.