Fix dependencies

docs/guide/installation-guide.txt

@@ -21,7 +21,6 @@ Troubleshooting
 The MongoDB driver depends on several other packages, including:
 
 * `bson <https://www.npmjs.com/package/bson>`_
-* `require_optional <https://www.npmjs.com/package/require_optional>`_
 * `safe-buffer <https://www.npmjs.com/package/safe-buffer>`_
 * `saslprep <https://www.npmjs.com/package/saslprep>`_
 

lib/core/connection/utils.js

@@ -1,7 +1,5 @@
 'use strict';
 
-const require_optional = require('require_optional');
-
 function debugOptions(debugFields, options) {
   var finaloptions = {};
   debugFields.forEach(function(n) {
@@ -16,7 +14,7 @@ function retrieveBSON() {
   BSON.native = false;
 
   try {
-    var optionalBSON = require_optional('bson-ext');
+    var optionalBSON = require('bson-ext');
     if (optionalBSON) {
       optionalBSON.native = true;
       return optionalBSON;
@@ -37,7 +35,7 @@ function noSnappyWarning() {
 function retrieveSnappy() {
   var snappy = null;
   try {
-    snappy = require_optional('snappy');
+    snappy = require('snappy');
   } catch (error) {} // eslint-disable-line
   if (!snappy) {
     snappy = {

lib/core/index.js

@@ -1,12 +1,11 @@
 'use strict';
 
 let BSON = require('bson');
-const require_optional = require('require_optional');
 const EJSON = require('./utils').retrieveEJSON();
 
 try {
   // Attempt to grab the native BSON parser
-  const BSONNative = require_optional('bson-ext');
+  const BSONNative = require('bson-ext');
   // If we got the native parser, use it instead of the
   // Javascript one
   if (BSONNative) {

lib/core/utils.js

@@ -1,7 +1,6 @@
 'use strict';
 const os = require('os');
 const crypto = require('crypto');
-const requireOptional = require('require_optional');
 
 /**
  * Generate a UUIDv4
@@ -27,7 +26,7 @@ function retrieveKerberos() {
   let kerberos;
 
   try {
-    kerberos = requireOptional('kerberos');
+    kerberos = require('kerberos');
   } catch (err) {
     if (err.code === 'MODULE_NOT_FOUND') {
       throw new Error('The `kerberos` module was not found. Please install it and try again.');
@@ -48,7 +47,7 @@ const noEJSONError = function() {
 function retrieveEJSON() {
   let EJSON = null;
   try {
-    EJSON = requireOptional('mongodb-extjson');
+    EJSON = require('mongodb-extjson');
   } catch (error) {} // eslint-disable-line
   if (!EJSON) {
     EJSON = {

package.json

@@ -16,18 +16,38 @@
     "driver",
     "official"
   ],
-  "peerOptionalDependencies": {
+  "peerDependencies": {
     "kerberos": "^1.1.0",
     "mongodb-client-encryption": "^1.0.0",
     "mongodb-extjson": "^2.1.2",
     "snappy": "^6.3.4",
-    "bson-ext": "^2.0.0"
+    "bson-ext": "^2.0.0",
+    "aws4": "^1.10.1"
+  },
+  "peerDependenciesMeta": {
+    "kerberos": {
+      "optional": true
+    },
+    "mongodb-client-encryption": {
+      "optional": true
+    },
+    "mongodb-extjson": {
+      "optional": true
+    },
+    "snappy": {
+      "optional": true
+    },
+    "bson-ext": {
+      "optional": true
+    },
+    "aws4": {
+      "optional": true
+    }
   },
   "dependencies": {
     "bl": "^2.2.1",
     "bson": "^1.1.4",
     "denque": "^1.4.1",
-    "require_optional": "^1.0.1",
     "safe-buffer": "^5.1.2"
   },
   "devDependencies": {