Merge pull request #88 from WebReflection/avoid-recusrion

Avoid recursion on parse due possible shenanigans

Author: WebReflection

README.md

@@ -16,15 +16,9 @@ Available also for **[Go](./golang/README.md)**.
 
 - - -
 
-## Announcement 📣
+## ℹ️ JSON only values
 
-There is a standard approach to recursion and more data-types than what JSON allows, and it's part of the [Structured Clone polyfill](https://github.com/ungap/structured-clone/#readme).
-
-Beside acting as a polyfill, its `@ungap/structured-clone/json` export provides both `stringify` and `parse`, and it's been tested for being faster than *flatted*, but its produced output is also smaller than *flatted* in general.
-
-The *@ungap/structured-clone* module is, in short, a drop in replacement for *flatted*, but it's not compatible with *flatted* specialized syntax.
-
-However, if recursion, as well as more data-types, are what you are after, or interesting for your projects/use cases, consider switching to this new module whenever you can 👍
+If you need anything more complex than values JSON understands, there is a standard approach to recursion and more data-types than what JSON allows, and it's part of the [Structured Clone polyfill](https://github.com/ungap/structured-clone/#readme).
 
 - - -
 

cjs/index.js

@@ -22,8 +22,7 @@ const Primitives = (_, value) => (
   typeof value === primitive ? new Primitive(value) : value
 );
 
-const revive = (input, parsed, output, $) => {
-  const lazy = [];
+const resolver = (input, lazy, parsed, $) => output => {
   for (let ke = keys(output), {length} = ke, y = 0; y < length; y++) {
     const k = ke[y];
     const value = output[k];
@@ -32,18 +31,14 @@ const revive = (input, parsed, output, $) => {
       if (typeof tmp === object && !parsed.has(tmp)) {
         parsed.add(tmp);
         output[k] = ignore;
-        lazy.push({k, a: [input, parsed, tmp, $]});
+        lazy.push({ o: output, k, r: tmp });
       }
       else
         output[k] = $.call(output, k, tmp);
     }
     else if (output[k] !== ignore)
       output[k] = $.call(output, k, value);
   }
-  for (let {length} = lazy, i = 0; i < length; i++) {
-    const {k, a} = lazy[i];
-    output[k] = $.call(output, k, revive.apply(null, a));
-  }
   return output;
 };
 
@@ -61,12 +56,24 @@ const set = (known, input, value) => {
  */
 const parse = (text, reviver) => {
   const input = $parse(text, Primitives).map(primitives);
-  const value = input[0];
   const $ = reviver || noop;
-  const tmp = typeof value === object && value ?
-              revive(input, new Set, value, $) :
-              value;
-  return $.call({'': tmp}, '', tmp);
+
+  let value = input[0];
+
+  if (typeof value === object && value) {
+    const lazy = [];
+    const revive = resolver(input, lazy, new Set, $);
+    value = revive(value);
+
+    let i = 0;
+    while (i < lazy.length) {
+      // it could be a lazy.shift() but that's costly
+      const {o, k, r} = lazy[i++];
+      o[k] = $.call(o, k, revive(r));
+    }
+  }
+
+  return $.call({'': value}, '', value);
 };
 exports.parse = parse;
 

es.js

@@ -21,8 +21,7 @@ const Primitives = (_, value) => (
   typeof value === primitive ? new Primitive(value) : value
 );
 
-const revive = (input, parsed, output, $) => {
-  const lazy = [];
+const resolver = (input, lazy, parsed, $) => output => {
   for (let ke = keys(output), {length} = ke, y = 0; y < length; y++) {
     const k = ke[y];
     const value = output[k];
@@ -31,18 +30,14 @@ const revive = (input, parsed, output, $) => {
       if (typeof tmp === object && !parsed.has(tmp)) {
         parsed.add(tmp);
         output[k] = ignore;
-        lazy.push({k, a: [input, parsed, tmp, $]});
+        lazy.push({ o: output, k, r: tmp });
       }
       else
         output[k] = $.call(output, k, tmp);
     }
     else if (output[k] !== ignore)
       output[k] = $.call(output, k, value);
   }
-  for (let {length} = lazy, i = 0; i < length; i++) {
-    const {k, a} = lazy[i];
-    output[k] = $.call(output, k, revive.apply(null, a));
-  }
   return output;
 };
 
@@ -60,12 +55,24 @@ const set = (known, input, value) => {
  */
 export const parse = (text, reviver) => {
   const input = $parse(text, Primitives).map(primitives);
-  const value = input[0];
   const $ = reviver || noop;
-  const tmp = typeof value === object && value ?
-              revive(input, new Set, value, $) :
-              value;
-  return $.call({'': tmp}, '', tmp);
+
+  let value = input[0];
+
+  if (typeof value === object && value) {
+    const lazy = [];
+    const revive = resolver(input, lazy, new Set, $);
+    value = revive(value);
+
+    let i = 0;
+    while (i < lazy.length) {
+      // it could be a lazy.shift() but that's costly
+      const {o, k, r} = lazy[i++];
+      o[k] = $.call(o, k, revive(r));
+    }
+  }
+
+  return $.call({'': value}, '', value);
 };
 
 /**

esm.js

@@ -32,30 +32,26 @@ self.Flatted = (function (exports) {
   var Primitives = function Primitives(_, value) {
     return _typeof(value) === primitive ? new Primitive(value) : value;
   };
-  var _revive = function revive(input, parsed, output, $) {
-    var lazy = [];
-    for (var ke = keys(output), length = ke.length, y = 0; y < length; y++) {
-      var k = ke[y];
-      var value = output[k];
-      if (value instanceof Primitive) {
-        var tmp = input[value];
-        if (_typeof(tmp) === object && !parsed.has(tmp)) {
-          parsed.add(tmp);
-          output[k] = ignore;
-          lazy.push({
-            k: k,
-            a: [input, parsed, tmp, $]
-          });
-        } else output[k] = $.call(output, k, tmp);
-      } else if (output[k] !== ignore) output[k] = $.call(output, k, value);
-    }
-    for (var _length = lazy.length, i = 0; i < _length; i++) {
-      var _lazy$i = lazy[i],
-        _k = _lazy$i.k,
-        a = _lazy$i.a;
-      output[_k] = $.call(output, _k, _revive.apply(null, a));
-    }
-    return output;
+  var resolver = function resolver(input, lazy, parsed, $) {
+    return function (output) {
+      for (var ke = keys(output), length = ke.length, y = 0; y < length; y++) {
+        var k = ke[y];
+        var value = output[k];
+        if (value instanceof Primitive) {
+          var tmp = input[value];
+          if (_typeof(tmp) === object && !parsed.has(tmp)) {
+            parsed.add(tmp);
+            output[k] = ignore;
+            lazy.push({
+              o: output,
+              k: k,
+              r: tmp
+            });
+          } else output[k] = $.call(output, k, tmp);
+        } else if (output[k] !== ignore) output[k] = $.call(output, k, value);
+      }
+      return output;
+    };
   };
   var set = function set(known, input, value) {
     var index = Primitive(input.push(value) - 1);
@@ -71,12 +67,25 @@ self.Flatted = (function (exports) {
    */
   var parse = function parse(text, reviver) {
     var input = $parse(text, Primitives).map(primitives);
-    var value = input[0];
     var $ = reviver || noop;
-    var tmp = _typeof(value) === object && value ? _revive(input, new Set(), value, $) : value;
+    var value = input[0];
+    if (_typeof(value) === object && value) {
+      var lazy = [];
+      var revive = resolver(input, lazy, new Set(), $);
+      value = revive(value);
+      var i = 0;
+      while (i < lazy.length) {
+        // it could be a lazy.shift() but that's costly
+        var _lazy$i = lazy[i++],
+          o = _lazy$i.o,
+          k = _lazy$i.k,
+          r = _lazy$i.r;
+        o[k] = $.call(o, k, revive(r));
+      }
+    }
     return $.call({
-      '': tmp
-    }, '', tmp);
+      '': value
+    }, '', value);
   };
 
   /**