improve performance of safeParse (#81)

* rename scan to filter

* improve performance of safeParse

* Fix Linting Issue

* add typing test for Array

Author: Uzlopak

index.js

@@ -10,14 +10,9 @@ function parse (text, reviver, options) {
     if (reviver !== null && typeof reviver === 'object') {
       options = reviver
       reviver = undefined
-    } else {
-      options = {}
     }
   }
 
-  const protoAction = options.protoAction || 'error'
-  const constructorAction = options.constructorAction || 'error'
-
   if (hasBuffer && Buffer.isBuffer(text)) {
     text = text.toString()
   }
@@ -30,13 +25,16 @@ function parse (text, reviver, options) {
   // Parse normally, allowing exceptions
   const obj = JSON.parse(text, reviver)
 
-  // options: 'error' (default) / 'remove' / 'ignore'
-  if (protoAction === 'ignore' && constructorAction === 'ignore') {
+  // Ignore null and non-objects
+  if (obj === null || typeof obj !== 'object') {
     return obj
   }
 
-  // Ignore null and non-objects
-  if (obj === null || typeof obj !== 'object') {
+  const protoAction = (options && options.protoAction) || 'error'
+  const constructorAction = (options && options.constructorAction) || 'error'
+
+  // options: 'error' (default) / 'remove' / 'ignore'
+  if (protoAction === 'ignore' && constructorAction === 'ignore') {
     return obj
   }
 
@@ -55,12 +53,10 @@ function parse (text, reviver, options) {
   }
 
   // Scan result for proto keys
-  scan(obj, { protoAction, constructorAction })
-
-  return obj
+  return filter(obj, { protoAction, constructorAction, safe: options && options.safe })
 }
 
-function scan (obj, { protoAction = 'error', constructorAction = 'error' } = {}) {
+function filter (obj, { protoAction = 'error', constructorAction = 'error', safe } = {}) {
   let next = [obj]
 
   while (next.length) {
@@ -69,7 +65,9 @@ function scan (obj, { protoAction = 'error', constructorAction = 'error' } = {})
 
     for (const node of nodes) {
       if (protoAction !== 'ignore' && Object.prototype.hasOwnProperty.call(node, '__proto__')) { // Avoid calling node.hasOwnProperty directly
-        if (protoAction === 'error') {
+        if (safe === true) {
+          return null
+        } else if (protoAction === 'error') {
           throw new SyntaxError('Object contains forbidden prototype property')
         }
 
@@ -79,7 +77,9 @@ function scan (obj, { protoAction = 'error', constructorAction = 'error' } = {})
       if (constructorAction !== 'ignore' &&
           Object.prototype.hasOwnProperty.call(node, 'constructor') &&
           Object.prototype.hasOwnProperty.call(node.constructor, 'prototype')) { // Avoid calling node.hasOwnProperty directly
-        if (constructorAction === 'error') {
+        if (safe === true) {
+          return null
+        } else if (constructorAction === 'error') {
           throw new SyntaxError('Object contains forbidden prototype property')
         }
 
@@ -89,23 +89,24 @@ function scan (obj, { protoAction = 'error', constructorAction = 'error' } = {})
       for (const key in node) {
         const value = node[key]
         if (value && typeof value === 'object') {
-          next.push(node[key])
+          next.push(value)
         }
       }
     }
   }
+  return obj
 }
 
 function safeParse (text, reviver) {
   try {
-    return parse(text, reviver)
+    return parse(text, reviver, { safe: true })
   } catch (ignoreError) {
     return null
   }
 }
 
 module.exports = {
   parse,
-  scan,
+  scan: filter,
   safeParse
 }

types/index.d.ts

@@ -5,30 +5,17 @@ export type ParseOptions = {
     * - `'remove'` - deletes any `__proto__` keys from the result object.
     * - `'ignore'` - skips all validation (same as calling `JSON.parse()` directly).
     */
-  protoAction?: 'error' | 'remove' | 'ignore',
+  protoAction?: 'error' | 'remove' | 'ignore';
   /**
    * What to do when a `constructor` key is found.
    * - `'error'` - throw a `SyntaxError` when a `constructor.prototype` key is found. This is the default value.
    * - `'remove'` - deletes any `constructor` keys from the result object.
    * - `'ignore'` - skips all validation (same as calling `JSON.parse()` directly).
    */
-  constructorAction?: 'error' | 'remove' | 'ignore',
+  constructorAction?: 'error' | 'remove' | 'ignore';
 }
 
-export type ScanOptions = {
-  /**
-   * What to do when a `__proto__` key is found.
-    * - `'error'` - throw a `SyntaxError` when a `__proto__` key is found. This is the default value.
-    * - `'remove'` - deletes any `__proto__` keys from the input `obj`.
-    */
-  protoAction?: 'error' | 'remove',
-  /**
-   * What to do when a `constructor` key is found.
-   * - `'error'` - throw a `SyntaxError` when a `constructor.prototype` key is found. This is the default value.
-   * - `'remove'` - deletes any `constructor` keys from the input `obj`.
-   */
-  constructorAction?: 'error' | 'remove',
-}
+export type ScanOptions = ParseOptions
 
 type Reviver = (this: any, key: string, value: any) => any
 
@@ -56,5 +43,6 @@ export function safeParse(text: string | Buffer, reviver?: Reviver | null): any
  *
  * @param obj The object being scanned.
  * @param options Optional configuration object.
+ * @returns The object, or `null` if onError is set to `nullify`
  */
-export function scan(obj: any, options?: ScanOptions): void
+export function scan(obj: {[key: string | number]: any }, options?: ParseOptions): any

types/index.test-d.ts

@@ -13,10 +13,11 @@ sjson.safeParse('"test"', null)
 sjson.safeParse('"test"')
 expectError(sjson.safeParse(null))
 
-sjson.scan('"test"', { protoAction: 'remove' })
-expectError(sjson.scan('"test"', { protoAction: 'ignore' }))
-sjson.scan('"test"', { constructorAction: 'error' })
-expectError(sjson.scan('"test"', { constructorAction: 'ignore' }))
+sjson.scan({}, { protoAction: 'remove' })
+sjson.scan({}, { protoAction: 'ignore' })
+sjson.scan({}, { constructorAction: 'error' })
+sjson.scan({}, { constructorAction: 'ignore' })
+sjson.scan(new Array(), {})
 
 declare const input: Buffer
 sjson.parse(input)