assert,util: lazy load comparison functions

PR-URL: https://github.com/nodejs/node/pull/20567
Reviewed-By: Gus Caplan <me@gus.host>
Reviewed-By: Matteo Collina <matteo.collina@gmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Jeremiah Senkpiel <fishrock123@rocketmail.com>

lib/assert.js

@@ -21,10 +21,6 @@
 'use strict';
 
 const { Buffer } = require('buffer');
-const {
-  isDeepEqual,
-  isDeepStrictEqual
-} = require('internal/util/comparisons');
 const { codes: {
   ERR_AMBIGUOUS_ARGUMENT,
   ERR_INVALID_ARG_TYPE,
@@ -37,6 +33,15 @@ const { inspect, types: { isPromise, isRegExp } } = require('util');
 const { EOL } = require('internal/constants');
 const { NativeModule } = require('internal/bootstrap/loaders');
 
+let isDeepEqual;
+let isDeepStrictEqual;
+
+function lazyLoadComparison() {
+  const comparison = require('internal/util/comparisons');
+  isDeepEqual = comparison.isDeepEqual;
+  isDeepStrictEqual = comparison.isDeepStrictEqual;
+}
+
 // Escape control characters but not \n and \t to keep the line breaks and
 // indentation intact.
 // eslint-disable-next-line no-control-regex
@@ -285,6 +290,7 @@ assert.notEqual = function notEqual(actual, expected, message) {
 
 // The equivalence assertion tests a deep equality relation.
 assert.deepEqual = function deepEqual(actual, expected, message) {
+  if (isDeepEqual === undefined) lazyLoadComparison();
   if (!isDeepEqual(actual, expected)) {
     innerFail({
       actual,
@@ -298,6 +304,7 @@ assert.deepEqual = function deepEqual(actual, expected, message) {
 
 // The non-equivalence assertion tests for any deep inequality.
 assert.notDeepEqual = function notDeepEqual(actual, expected, message) {
+  if (isDeepEqual === undefined) lazyLoadComparison();
   if (isDeepEqual(actual, expected)) {
     innerFail({
       actual,
@@ -311,6 +318,7 @@ assert.notDeepEqual = function notDeepEqual(actual, expected, message) {
 /* eslint-enable */
 
 assert.deepStrictEqual = function deepStrictEqual(actual, expected, message) {
+  if (isDeepEqual === undefined) lazyLoadComparison();
   if (!isDeepStrictEqual(actual, expected)) {
     innerFail({
       actual,
@@ -324,6 +332,7 @@ assert.deepStrictEqual = function deepStrictEqual(actual, expected, message) {
 
 assert.notDeepStrictEqual = notDeepStrictEqual;
 function notDeepStrictEqual(actual, expected, message) {
+  if (isDeepEqual === undefined) lazyLoadComparison();
   if (isDeepStrictEqual(actual, expected)) {
     innerFail({
       actual,
@@ -437,6 +446,7 @@ function expectedException(actual, expected, msg) {
       throw new ERR_INVALID_ARG_VALUE('error',
                                       expected, 'may not be an empty object');
     }
+    if (isDeepEqual === undefined) lazyLoadComparison();
     for (const key of keys) {
       if (typeof actual[key] === 'string' &&
           isRegExp(expected[key]) &&

lib/util.js

@@ -64,10 +64,6 @@ const {
   isTypedArray
 } = types;
 
-const {
-  isDeepStrictEqual
-} = require('internal/util/comparisons');
-
 const {
   customInspectSymbol,
   deprecate,
@@ -95,6 +91,7 @@ const dateToISOString = Date.prototype.toISOString;
 const errorToString = Error.prototype.toString;
 
 let CIRCULAR_ERROR_MESSAGE;
+let internalDeepEqual;
 
 /* eslint-disable */
 const strEscapeSequencesRegExp = /[\x00-\x1f\x27\x5c]/;
@@ -1261,7 +1258,13 @@ module.exports = exports = {
   isArray: Array.isArray,
   isBoolean,
   isBuffer,
-  isDeepStrictEqual,
+  isDeepStrictEqual(a, b) {
+    if (internalDeepEqual === undefined) {
+      internalDeepEqual = require('internal/util/comparisons')
+        .isDeepStrictEqual;
+    }
+    return internalDeepEqual(a, b);
+  },
   isNull,
   isNullOrUndefined,
   isNumber,