Variable Loader

Type declaration

• dependencyKeysIfEvaluated: ((specifier: string) => string[])

  • • (specifier: string): string[]

    • For an already-evaluated module, return the dependencies as module specifiers

      This list is already sorted and uniqued.

      Example

      For this code:

      // /foo.js
      import classNames from 'classnames';
      import React from 'react';
      import {createElement} from 'react';
      

      This would return:

      Loader.dependencyKeysIfEvaluated("/foo.js")
      ["bun:wrap", "/path/to/node_modules/classnames/index.js", "/path/to/node_modules/react/index.js"]
      

      Parameters

      • specifier: string

        module specifier as it appears in transpiled source code

      Returns string[]

• registry: Map<string, { dependencies: string[]; module: any; state: number }>

  ESM module registry

  This lets you implement live reload in Bun. If you delete a module specifier from this map, the next time it's imported, it will be re-transpiled and loaded again.

  The keys are the module specifiers and the values are metadata about the module.

  The keys are an implementation detail for Bun that will change between versions.

  • Userland modules are an absolute file path
  • Virtual modules have a bun: prefix or node: prefix
  • JS polyfills start with "/bun-vfs/". "buffer" is an example of a JS polyfill
  • If you have a node_modules.bun file, many modules will point to that file

  Virtual modules and JS polyfills are embedded in bun's binary. They don't point to anywhere in your local filesystem.

• resolve: ((specifier: string) => Promise<string>)

  • • (specifier: string): Promise<string>

    • The function JavaScriptCore internally calls when you use an import statement.

      This may return a path to node_modules.server.bun, which will be confusing.

      Consider Bun.resolve or ImportMeta.resolve instead.

      Parameters

      • specifier: string

        module specifier as it appears in transpiled source code

      Returns Promise<string>

• resolveSync: ((specifier: string, from: string) => string)

  • • (specifier: string, from: string): string

    • Synchronously resolve a module specifier

      This may return a path to node_modules.server.bun, which will be confusing.

      Consider Bun.resolveSync instead.

      Parameters

      • specifier: string

      • from: string

      Returns string