Added support for stringifyPrepare/finalize

README.md

@@ -99,6 +99,25 @@ var parse = require('warp10/parse');
 var object = parse(json);
 ```
 
+## JSON stringifyPrepare/finalize
+
+The `stringifyPrepare` function can be used to produce a JavaScript object that is safe to serialize using the native `JSON.stringify` method. The `finalize` method should be called on the parsed object to produce the final object with duplicate objects and circular dependencies intact.
+
+_On the server:_
+
+```javascript
+var warp10 = require('warp10').stringifyPrepare;
+var object = stringifyPrepare(object); // Returns an Object
+var json = JSON.stringify(object);
+```
+
+_In the browser:_
+
+```javascript
+var finalize = require('warp10/finalize');
+var clone = finalize(JSON.parse(json));
+```
+
 # Examples
 
 ## Serialize examples

finalize.js

@@ -0,0 +1 @@
+module.exports = require('./src/finalize');

src/finalize.js

@@ -0,0 +1,50 @@
+var isArray = Array.isArray;
+
+function resolve(object, path, len) {
+    var current = object;
+    for (var i=0; i<len; i++) {
+        current = current[path[i]];
+    }
+
+    return current;
+}
+
+function resolveType(info) {
+    if (info.type === 'Date') {
+        return new Date(info.value);
+    } else {
+        throw new Error('Bad type');
+    }
+}
+
+module.exports = function parse(outer) {
+    var object = outer.object;
+
+    var assignments = outer.assignments;
+    if (assignments) {
+        for (var i=0, len=assignments.length; i<len; i++) {
+            var assignment = assignments[i];
+
+            var rhs = assignment.r;
+            var rhsValue;
+
+            if (isArray(rhs)) {
+                rhsValue = resolve(object, rhs, rhs.length);
+            } else {
+                rhsValue = resolveType(rhs);
+            }
+
+            var lhs = assignment.l;
+            var lhsLast = lhs.length-1;
+
+            if (lhsLast === -1) {
+                return rhsValue;
+            } else {
+                var lhsParent = resolve(object, lhs, lhsLast);
+                lhsParent[lhs[lhsLast]] = rhsValue;
+            }
+        }
+    }
+
+    return object == null ? null : object;
+};

src/index.js

@@ -1,4 +1,6 @@
 'use strict';
 exports.serialize = require('./serialize');
 exports.stringify = require('./stringify');
-exports.parse = require('./parse');
+exports.parse = require('./parse');
+exports.finalize = require('./finalize');
+exports.stringifyPrepare = require('./stringifyPrepare');

src/parse.js

@@ -1,52 +1,6 @@
-var isArray = Array.isArray;
-
-function resolve(object, path, len) {
-    var current = object;
-    for (var i=0; i<len; i++) {
-        current = current[path[i]];
-    }
-
-    return current;
-}
-
-function resolveType(info) {
-    if (info.type === 'Date') {
-        return new Date(info.value);
-    } else {
-        throw new Error('Bad type');
-    }
-}
+var finalize = require('./finalize');
 
 module.exports = function parse(json) {
     var outer = JSON.parse(json);
-
-    var object = outer.object;
-
-    var assignments = outer.assignments;
-    if (assignments) {
-        for (var i=0, len=assignments.length; i<len; i++) {
-            var assignment = assignments[i];
-
-            var rhs = assignment.r;
-            var rhsValue;
-
-            if (isArray(rhs)) {
-                rhsValue = resolve(object, rhs, rhs.length);
-            } else {
-                rhsValue = resolveType(rhs);
-            }
-
-            var lhs = assignment.l;
-            var lhsLast = lhs.length-1;
-
-            if (lhsLast === -1) {
-                return rhsValue;
-            } else {
-                var lhsParent = resolve(object, lhs, lhsLast);
-                lhsParent[lhs[lhsLast]] = rhsValue;
-            }
-        }
-    }
-
-    return object == null ? null : object;
+    return finalize(outer);
 };

src/stringify.js

@@ -1,139 +1,6 @@
 'use strict';
-const markerKey = Symbol('warp10');
+const stringifyPrepare = require('./stringifyPrepare');
 const escapeEndingScriptTagRegExp = /<\//g;
-const isArray = Array.isArray;
-
-class Marker {
-    constructor(path, symbol) {
-        this.path = path;
-        this.symbol = symbol;
-    }
-}
-
-function append(array, el) {
-    var len = array.length;
-    var clone = new Array(len+1);
-    for (var i=0; i<len; i++) {
-        clone[i] = array[i];
-    }
-    clone[len] = el;
-    return clone;
-}
-
-class Assignment {
-    constructor(lhs, rhs) {
-        this.l = lhs;
-        this.r = rhs;
-    }
-}
-
-function handleProperty(clone, key, value, valuePath, serializationSymbol, assignments) {
-    if (value.constructor === Date) {
-        assignments.push(new Assignment(valuePath, { type: 'Date', value: value.getTime() }));
-    } else if (isArray(value)) {
-        const marker = value[markerKey];
-
-        if (marker && marker.symbol === serializationSymbol) {
-            assignments.push(new Assignment(valuePath, marker.path));
-        } else {
-            value[markerKey] = new Marker(valuePath, serializationSymbol);
-            clone[key] = pruneArray(value, valuePath, serializationSymbol, assignments);
-        }
-    } else {
-        const marker = value[markerKey];
-        if (marker && marker.symbol === serializationSymbol) {
-            assignments.push(new Assignment(valuePath, marker.path));
-        } else {
-            value[markerKey] = new Marker(valuePath, serializationSymbol);
-            clone[key] = pruneObject(value, valuePath, serializationSymbol, assignments);
-        }
-    }
-}
-
-function pruneArray(array, path, serializationSymbol, assignments) {
-    let len = array.length;
-
-    var clone = new Array(len);
-
-    for (let i=0; i<len; i++) {
-        var value = array[i];
-        if (value == null) {
-            continue;
-        }
-
-        if (value && typeof value === 'object') {
-            handleProperty(clone, i, value, append(path, i), serializationSymbol, assignments);
-        } else {
-            clone[i] = value;
-        }
-    }
-
-    return clone;
-}
-
-function pruneObject(obj, path, serializationSymbol, assignments) {
-    var clone = {};
-
-    for (var key in obj) {
-        var value = obj[key];
-        if (value == null) {
-            continue;
-        }
-
-        if (value && typeof value === 'object') {
-            handleProperty(clone, key, value, append(path, key), serializationSymbol, assignments);
-        } else {
-            clone[key] = value;
-        }
-    }
-
-    return clone;
-}
-
-function stringifyHelper(obj, safe) {
-    /**
-     * Performance notes:
-     *
-     * - It is faster to use native JSON.stringify instead of a custom stringify
-     * - It is faster to first prune and then call JSON.stringify with _no_ replacer
-     */
-    var pruned;
-
-    const assignments = []; // Used to keep track of code that needs to run to fix up the stringified object
-
-    if (typeof obj === 'object') {
-        const serializationSymbol = Symbol(); // Used to detect if the marker is associated with _this_ serialization
-        const path = [];
-
-        obj[markerKey] = new Marker(path, serializationSymbol);
-
-        if (obj.constructor === Date) {
-            pruned = null;
-            assignments.push(new Assignment([], { type: 'Date', value: obj.getTime() }));
-        } else if (isArray(obj)) {
-            pruned = pruneArray(obj, path, serializationSymbol, assignments);
-        } else {
-            pruned = pruneObject(obj, path, serializationSymbol, assignments);
-        }
-    } else {
-        pruned = obj;
-    }
-
-    var final = {
-        object: pruned
-    };
-
-    if (assignments.length) {
-        final.assignments = assignments;
-    }
-
-    let json = JSON.stringify(final);
-    if (safe) {
-        json = json.replace(escapeEndingScriptTagRegExp, '\\u003C/');
-    }
-
-    return json;
-}
 
 module.exports = function stringify(obj, options) {
     if (obj == null) {
@@ -148,5 +15,12 @@ module.exports = function stringify(obj, options) {
         safe = false;
     }
 
-    return stringifyHelper(obj, safe);
+    var final = stringifyPrepare(obj);
+
+    let json = JSON.stringify(final);
+    if (safe) {
+        json = json.replace(escapeEndingScriptTagRegExp, '\\u003C/');
+    }
+
+    return json;
 };