fix: deprecate cacheFunctionsCrc32

The `crc32` function was never implemented, as a result this property never worked as intended. Deprecates the `cacheFunctionsCrc32` property from deserialize options, and removes it from documentation.

NODE-2770

Author: Thomas Reggi

README.md

@@ -193,7 +193,7 @@ Starting with Angular 6, Angular CLI removed the shim for `global` and other nod
 Parse an Extended JSON string, constructing the JavaScript value or object described by that
 string.
 
-**Example**  
+**Example**
 ```js
 const { EJSON } = require('bson');
 const text = '{ "int32": { "$numberInt": "10" } }';
@@ -221,7 +221,7 @@ Converts a BSON document to an Extended JSON string, optionally replacing values
 function is specified or optionally including only the specified properties if a replacer array
 is specified.
 
-**Example**  
+**Example**
 ```js
 const { EJSON } = require('bson');
 const Int32 = require('mongodb').Int32;
@@ -278,7 +278,7 @@ Sets the size of the internal serialization buffer.
 
 Serialize a Javascript object.
 
-**Returns**: <code>Buffer</code> - returns the Buffer object containing the serialized object.  
+**Returns**: <code>Buffer</code> - returns the Buffer object containing the serialized object.
 <a name="serializeWithBufferAndIndex"></a>
 
 ### serializeWithBufferAndIndex(object, buffer)
@@ -294,7 +294,7 @@ Serialize a Javascript object.
 
 Serialize a Javascript object using a predefined Buffer and index into the buffer, useful when pre-allocating the space for serialization.
 
-**Returns**: <code>Number</code> - returns the index pointing to the last written byte in the buffer.  
+**Returns**: <code>Number</code> - returns the index pointing to the last written byte in the buffer.
 <a name="deserialize"></a>
 
 ### deserialize(buffer)
@@ -304,7 +304,6 @@ Serialize a Javascript object using a predefined Buffer and index into the buffe
 | buffer | <code>Buffer</code> |  | the buffer containing the serialized set of BSON documents. |
 | [options.evalFunctions] | <code>Object</code> | <code>false</code> | evaluate functions in the BSON document scoped to the object deserialized. |
 | [options.cacheFunctions] | <code>Object</code> | <code>false</code> | cache evaluated functions for reuse. |
-| [options.cacheFunctionsCrc32] | <code>Object</code> | <code>false</code> | use a crc32 code for caching, otherwise use the string of the function. |
 | [options.promoteLongs] | <code>Object</code> | <code>true</code> | when deserializing a Long will fit it into a Number if it's smaller than 53 bits |
 | [options.promoteBuffers] | <code>Object</code> | <code>false</code> | when deserializing a Binary will return it as a node.js Buffer instance. |
 | [options.promoteValues] | <code>Object</code> | <code>false</code> | when deserializing will promote BSON values to their Node.js closest equivalent types. |
@@ -314,7 +313,7 @@ Serialize a Javascript object using a predefined Buffer and index into the buffe
 
 Deserialize data as BSON.
 
-**Returns**: <code>Object</code> - returns the deserialized Javascript Object.  
+**Returns**: <code>Object</code> - returns the deserialized Javascript Object.
 <a name="calculateObjectSize"></a>
 
 ### calculateObjectSize(object)
@@ -327,7 +326,7 @@ Deserialize data as BSON.
 
 Calculate the bson size for a passed in Javascript object.
 
-**Returns**: <code>Number</code> - returns the number of bytes the BSON object will take up.  
+**Returns**: <code>Number</code> - returns the number of bytes the BSON object will take up.
 <a name="deserializeStream"></a>
 
 ### deserializeStream(data, startIndex, numberOfDocuments, documents, docStartIndex, [options])
@@ -342,7 +341,6 @@ Calculate the bson size for a passed in Javascript object.
 | [options] | <code>Object</code> |  | additional options used for the deserialization. |
 | [options.evalFunctions] | <code>Object</code> | <code>false</code> | evaluate functions in the BSON document scoped to the object deserialized. |
 | [options.cacheFunctions] | <code>Object</code> | <code>false</code> | cache evaluated functions for reuse. |
-| [options.cacheFunctionsCrc32] | <code>Object</code> | <code>false</code> | use a crc32 code for caching, otherwise use the string of the function. |
 | [options.promoteLongs] | <code>Object</code> | <code>true</code> | when deserializing a Long will fit it into a Number if it's smaller than 53 bits |
 | [options.promoteBuffers] | <code>Object</code> | <code>false</code> | when deserializing a Binary will return it as a node.js Buffer instance. |
 | [options.promoteValues] | <code>Object</code> | <code>false</code> | when deserializing will promote BSON values to their Node.js closest equivalent types. |
@@ -351,7 +349,7 @@ Calculate the bson size for a passed in Javascript object.
 
 Deserialize stream data as BSON documents.
 
-**Returns**: <code>Number</code> - returns the next index in the buffer after deserialization **x** numbers of documents.  
+**Returns**: <code>Number</code> - returns the next index in the buffer after deserialization **x** numbers of documents.
 
 ## FAQ
 

src/parser/deserializer.ts

@@ -21,7 +21,11 @@ export interface DeserializeOptions {
   evalFunctions?: boolean;
   /** cache evaluated functions for reuse. */
   cacheFunctions?: boolean;
-  /** use a crc32 code for caching, otherwise use the string of the function. */
+  /**
+   * use a crc32 code for caching, otherwise use the string of the function.
+   * @deprecated this option to use the crc32 function never worked as intended
+   * due to the fact that the crc32 function itself was never implemented.
+   * */
   cacheFunctionsCrc32?: boolean;
   /** when deserializing a Long will fit it into a Number if it's smaller than 53 bits */
   promoteLongs?: boolean;
@@ -98,15 +102,6 @@ function deserializeObject(
 ) {
   const evalFunctions = options['evalFunctions'] == null ? false : options['evalFunctions'];
   const cacheFunctions = options['cacheFunctions'] == null ? false : options['cacheFunctions'];
-  const cacheFunctionsCrc32 =
-    options['cacheFunctionsCrc32'] == null ? false : options['cacheFunctionsCrc32'];
-
-  let crc32;
-  if (!cacheFunctionsCrc32) {
-    crc32 = null;
-  } else {
-    crc32 = (v: string) => v; // FIXME(NODE-2770): This is a bug, hashing function is missing.
-  }
 
   const fieldsAsRaw = options['fieldsAsRaw'] == null ? null : options['fieldsAsRaw'];
 
@@ -499,9 +494,8 @@ function deserializeObject(
       if (evalFunctions) {
         // If we have cache enabled let's look for the md5 of the function in the cache
         if (cacheFunctions) {
-          const hash = cacheFunctionsCrc32 && crc32 ? crc32(functionString) : functionString;
           // Got to do this to avoid V8 deoptimizing the call due to finding eval
-          object[name] = isolateEvalWithHash(functionCache, hash, functionString, object);
+          object[name] = isolateEval(functionString, functionCache, object);
         } else {
           object[name] = isolateEval(functionString);
         }
@@ -568,9 +562,8 @@ function deserializeObject(
       if (evalFunctions) {
         // If we have cache enabled let's look for the md5 of the function in the cache
         if (cacheFunctions) {
-          const hash = cacheFunctionsCrc32 && crc32 ? crc32(functionString) : functionString;
           // Got to do this to avoid V8 deoptimizing the call due to finding eval
-          object[name] = isolateEvalWithHash(functionCache, hash, functionString, object);
+          object[name] = isolateEval(functionString, functionCache, object);
         } else {
           object[name] = isolateEval(functionString);
         }
@@ -654,26 +647,17 @@ function deserializeObject(
  *
  * @internal
  */
-function isolateEvalWithHash(
-  functionCache: { [hash: string]: Function },
-  hash: string,
+function isolateEval(
   functionString: string,
-  object: Document
+  functionCache?: { [hash: string]: Function },
+  object?: Document
 ) {
+  if (!functionCache) return new Function(functionString);
   // Check for cache hit, eval if missing and return cached function
-  if (functionCache[hash] == null) {
-    functionCache[hash] = new Function(functionString);
+  if (functionCache[functionString] == null) {
+    functionCache[functionString] = new Function(functionString);
   }
 
   // Set the object
-  return functionCache[hash].bind(object);
-}
-
-/**
- * Ensure eval is isolated.
- *
- * @internal
- */
-function isolateEval(functionString: string): Function {
-  return new Function(functionString);
+  return functionCache[functionString].bind(object);
 }