[New] extract isCore implementation to is-core-module

lib/async.js

@@ -3,7 +3,7 @@ var path = require('path');
 var caller = require('./caller.js');
 var nodeModulesPaths = require('./node-modules-paths.js');
 var normalizeOptions = require('./normalize-options.js');
-var isCore = require('./is-core');
+var isCore = require('is-core-module');
 
 var realpathFS = fs.realpath && typeof fs.realpath.native === 'function' ? fs.realpath.native : fs.realpath;
 

lib/core.js

@@ -1,3 +1,5 @@
+console.warn('`resolve/lib/core` is deprecated; please use `is-core-module` directly');
+
 var current = (process.versions && process.versions.node && process.versions.node.split('.')) || [];
 
 function specifierIncluded(specifier) {

lib/is-core.js

@@ -1,5 +1,5 @@
-var core = require('./core');
+var isCoreModule = require('is-core-module');
 
 module.exports = function isCore(x) {
-    return Object.prototype.hasOwnProperty.call(core, x);
+    return isCoreModule(x);
 };

lib/sync.js

@@ -1,4 +1,4 @@
-var isCore = require('./is-core');
+var isCore = require('is-core-module');
 var fs = require('fs');
 var path = require('path');
 var caller = require('./caller.js');

package.json

@@ -14,8 +14,8 @@
 		"module"
 	],
 	"scripts": {
-		"prepublish": "safe-publish-latest",
-		"lint": "eslint .",
+		"prepublish": "safe-publish-latest && cp node_modules/is-core-module/core.json ./lib/",
+		"lint": "eslint --ext=js,mjs .",
 		"pretests-only": "cd ./test/resolver/nested_symlinks && node mylib/sync && node mylib/async",
 		"tests-only": "tape test/*.js",
 		"pretest": "npm run lint",
@@ -42,6 +42,7 @@
 		"url": "https://github.com/sponsors/ljharb"
 	},
 	"dependencies": {
+		"is-core-module": "^2.0.0",
 		"path-parse": "^1.0.6"
 	}
 }