A tiny (727b), correct, general-purpose, and configurable "exports" resolver without file-system reliance. 

A tiny (952b), correct, general-purpose, and configurable "exports" and "imports" resolver without file-system reliance

lukeed

resolve.exports

A tiny (727b), correct, general-purpose, and configurable "exports" resolver without file-system reliance

			for (idx=0; idx < exports.length; idx++) {

				if (tmp = loop(exports[idx], keys)) return tmp;

 * @param {string} entry The target entry, eg "."

 * @param {number} [condition] Unmatched condition?

		? `No known conditions for "${entry}" entry in "${name}" package`

		: `Missing "${entry}" export in "${name}" package`

 * @param {string} entry the target path/import

		: entry.replace(new RegExp('^' + name + '\/'), './');

 * @param {object} pkg package.json contents

 * @param {string} [entry] entry name or import path

 * @param {string[]} [options.conditions]

function resolve(pkg, entry='.', options={}) {

		let { browser, require, conditions=[] } = options;

		if (target[0] !== '.') target = './' + target;

			return target === '.' ? exports : bail(name, target);

		let allows = new Set(['default', ...conditions]);

		allows.add(require ? 'require' : 'import');

		allows.add(browser ? 'browser' : 'node');

				? loop(exports, allows) || bail(name, target, 1)

			return loop(tmp, allows) || bail(name, target, 1);

			if (tmp === '/' && target.startsWith(key)) {

				return exports[key] + target.substring(key.length);

				return (tmp = loop(exports[key], allows))

					? (tmp + target.substring(key.length))

			if (tmp === '*' && target.startsWith(key.slice(0, -1))) {

				// do not trigger if no *content* to inject

				if (tmp = target.substring(key.length - 1)) {

					return exports[key].replace('*', tmp);

				if (target.length - key.length > 1) {

					return (tmp = loop(exports[key], allows))

						? tmp.replace('*', target.substring(key.length - 1))

 * @param {string|boolean} [options.browser]

		fields = options.fields || ['module', 'main'];

	if (browser && !fields.includes('browser')) {

			} else if (typeof value == 'object' && fields[i] == 'browser') {

					value = value[browser=toName(pkg.name, browser)];

				? ('./' + value.replace(/^\.?\//, ''))

  "repository": "lukeed/resolve.exports",

  "description": "A tiny (710b), correct, general-purpose, and configurable \"exports\" resolver without file-system reliance",

  "description": "A tiny (727b), correct, general-purpose, and configurable \"exports\" resolver without file-system reliance",

# resolve.exports [![CI](https://github.com/lukeed/resolve.exports/workflows/CI/badge.svg)](https://github.com/lukeed/resolve.exports/actions) [![codecov](https://badgen.net/codecov/c/github/lukeed/resolve.exports)](https://codecov.io/gh/lukeed/resolve.exports)

> A tiny (710b), correct, general-purpose, and configurable `"exports"` resolver without file-system reliance

> A tiny (727b), correct, general-purpose, and configurable `"exports"` resolver without file-system reliance

Hopefully, this module may serve as a reference point (and/or be used directly) so that the varying tools and bundlers within the ecosystem can share a common approach with one another **as well as** with the native Node.js implementation.

With the push for ESM, we must be _very_ careful and avoid fragmentation. If we, as a community, begin propagating different _dialects_ of `"exports"` resolution, then we're headed for deep trouble. It will make supporting (and using) `"exports"` nearly impossible, which may force its abandonment and along with it, its benefits.

- [x] directory mapping (`./foobar/` => `/foobar/`)

- [x] directory mapping (`./foobar/*` => `./other/*.js`)

- [x] directory mapping w/ nested conditions

- [x] legacy fields (`main` vs `module` vs ...)

> Please see [`/test/`](/test) for examples.

import { resolve, legacy } from 'resolve.exports';

        "browser": "./lite/worker.brower.js",

resolve(contents); //=> "./dist/module.mjs"

resolve(contents, 'foobar'); //=> "./dist/module.mjs"

resolve(contents, '.'); //=> "./dist/module.mjs"

resolve(contents, 'foobar/lite'); //=> "./lite/module.mjs"

resolve(contents, './lite'); //=> "./lite/module.mjs"

resolve(contents, 'foobar', { require: true }); //=> "./dist/require.js"

resolve(contents, './lite', { require: true }); //=> "./lite/require.js"

// Throws "Missing <entry> export in <name> package" Error

Traverse the `"exports"` within the contents of a `package.json` file. <br>

If the contents _does not_ contain an `"exports"` map, then `undefined` will be returned.

Successful resolutions will always result in a string value. This will be the value of the resolved mapping itself – which means that the output is a relative file path.

* the requested `entry` cannot be resolved (aka, not defined in the `"exports"` map)

* an `entry` _was_ resolved but no known conditions were found (see [`options.conditions`](#optionsconditions))

		{
		"version": "1.0.0",
		"version": "1.0.1",
		"name": "resolve.exports",
		"repository": "lukeed/resolve.exports",
		"description": "A tiny (710b), correct, general-purpose, and configurable \"exports\" resolver without file-system reliance",
		"description": "A tiny (727b), correct, general-purpose, and configurable \"exports\" resolver without file-system reliance",
		"module": "dist/index.mjs",
		@@ -7,0 +7,0 @@ "main": "dist/index.js",

		@@ -94,8 +94,12 @@ /**
		if (tmp === '/' && target.startsWith(key)) {
		return exports[key] + target.substring(key.length);
		return (tmp = loop(exports[key], allows))
		? (tmp + target.substring(key.length))
		: bail(name, target, 1);
		}
		if (tmp === '*' && target.startsWith(key.slice(0, -1))) {
		// do not trigger if no content to inject
		if (tmp = target.substring(key.length - 1)) {
		return exports[key].replace('*', tmp);
		if (target.length - key.length > 1) {
		return (tmp = loop(exports[key], allows))
		? tmp.replace('*', target.substring(key.length - 1))
		: bail(name, target, 1);
		}
		@@ -102,0 +106,0 @@ }

Improved metrics