Add serializeAnyToJson and unserializeAnyFromJsonUnsafe

jscomp/others/js_json.ml

@@ -129,3 +129,88 @@ external stringify: t -> string = "stringify"
   [@@bs.val] [@@bs.scope "JSON"]
 external stringifyWithSpace: t -> (_ [@bs.as {json|null|json}]) -> int -> string = "stringify" 
   [@@bs.val] [@@bs.scope "JSON"]
+
+type preJson
+let _toJson: preJson -> t = fun%raw data -> {|
+  if (!data) {
+    return data
+  } else if (typeof data === 'function') {
+    throw new Error("Cannot serialize a function")
+  } else if (Array.isArray(data)) {
+    if (data.tag != null) {
+      return {
+        $$tag: data.tag,
+        $$contents: data.map(_toJson),
+        $$bsVariant: data[Symbol.for('BsVariant')],
+      }
+    } else if (data[Symbol.for('BsVariant')] != null) {
+      return {
+        $$bsVariant: data[Symbol.for('BsVariant')],
+        $$contents: data.map(_toJson)
+      }
+    } else if (data[Symbol.for('BsLocalModule')] != null) {
+      return {
+        $$bsLocalModule: data[Symbol.for('BsLocalModule')],
+        $$contents: data.map(_toJson)
+      }
+    } else if (data[Symbol.for('BsPolyVar')] != null) {
+      return {
+        $$bsPolyVar: data[Symbol.for('BsPolyVar')],
+        $$contents: data.map(_toJson)
+      }
+    } else if (data[Symbol.for('BsRecord')] != null) {
+      return {
+        $$bsRecord: data[Symbol.for('BsRecord')],
+        $$contents: data.map(_toJson)
+      }
+    } else {
+      return data.map(_toJson)
+    }
+  } else if (typeof data == 'object') {
+    var result = {}
+    Object.keys(data).forEach(key => result[key] = _toJson(data[key]))
+    return result
+  } else {
+    return data
+  }
+|}
+
+(** This dance is required to appease the type checker -- doing 
+ * `toJson: 'a -> t = fun%raw` gives the error "contains type variables
+ * that cannot be generalized". *)
+external toT : 'a -> preJson = "%identity"
+let serializeAnyToJson data = _toJson (toT data)
+
+let unserializeAnyFromJsonUnsafe: t -> 'a = fun%raw data -> {|
+  if (!data) {
+    return data
+  } else if (typeof data == 'object') {
+    if (Array.isArray(data)) {
+      return data.map(unserializeAnyFromJsonUnsafe)
+    } else if (data.$$contents) {
+      var result = data.$$contents.map(unserializeAnyFromJsonUnsafe)
+      if (data.$$tag != null) {
+        result.tag = data.$$tag
+      }
+      if (data.$$bsRecord) {
+        result[Symbol.for('BsRecord')] = data.$$bsRecord
+      }
+      if (data.$$bsPolyVar) {
+        result[Symbol.for('BsPolyVar')] = data.$$bsPolyVar
+      }
+      if (data.$$bsVariant) {
+        result[Symbol.for('BsVariant')] = data.$$bsVariant
+      }
+      if (data.$$bsLocalModule) {
+        result[Symbol.for('BsLocalModule')] = data.$$bsLocalModule
+      }
+      return result
+    } else {
+      var result = {}
+      Object.keys(data).forEach(key => result[key] = unserializeAnyFromJsonUnsafe(data[key]))
+      return result
+    }
+  } else {
+    return data
+  }
+|}

jscomp/others/js_json.mli

@@ -236,4 +236,25 @@ Js.log \@\@ Js.Json.stringify [| "foo"; "bar" |]
 *)
 
 
+val serializeAnyToJson : 'a -> t
+(** [anyToJson value] turns any [value] into a JSON object
 
+This will throw an error if there are any functions anywhere in the value.
+*)
+
+
+val unserializeAnyFromJsonUnsafe : t -> 'a
+(** [unsafeAnyFromJson json] converts a serialized JSON object back into the bucklescript runtime value.
+
+Warning: marshaling is currently not type-safe. The type of marshaled data is not transmitted along
+the value of the data, making it impossible to check that the data read back possesses the type expected
+by the context. The return type of this function is given as 'a, but this is misleading: the returned
+OCaml value does not possess type 'a for all 'a; it has one, unique type which cannot be determined at
+compile-time.
+
+The programmer should explicitly give the expected type of the returned value, using the following syntax:
+
+  (Js.Json.unserializeAnyFromJsonUnsafe json : type)
+
+Anything can happen at run-time if the object does not correspond to the assumed type.
+*)

jscomp/test/js_json_test.js

@@ -6,6 +6,7 @@ var Block = require("../../lib/js/block.js");
 var Js_json = require("../../lib/js/js_json.js");
 var Caml_array = require("../../lib/js/caml_array.js");
 var Js_primitive = require("../../lib/js/js_primitive.js");
+var Belt_MapString = require("../../lib/js/belt_MapString.js");
 var Caml_builtin_exceptions = require("../../lib/js/caml_builtin_exceptions.js");
 
 var suites = /* record */[/* contents : [] */0];
@@ -585,6 +586,61 @@ eq("File \"js_json_test.ml\", line 387, characters 5-12", Js_json.decodeNull({ }
 
 eq("File \"js_json_test.ml\", line 389, characters 5-12", Js_json.decodeNull(1.23), undefined);
 
+function check(loc, value) {
+  return eq(loc, Js_json.unserializeAnyFromJsonUnsafe(Js_json.serializeAnyToJson(value)), value);
+}
+
+check("File \"js_json_test.ml\", line 398, characters 8-15", /* record */[
+      /* a */2,
+      /* b */undefined,
+      /* c : Ok */Block.__(0, ["folks"]),
+      /* d : [] */0
+    ]);
+
+check("File \"js_json_test.ml\", line 399, characters 8-15", /* :: */[
+      /* tuple */[
+        2,
+        3,
+        4,
+        5
+      ],
+      /* [] */0
+    ]);
+
+check("File \"js_json_test.ml\", line 400, characters 8-15", /* `Poly */[
+      892709484,
+      3
+    ]);
+
+check("File \"js_json_test.ml\", line 401, characters 8-15", Belt_MapString.set(Belt_MapString.set(Belt_MapString.empty, "hello", /* :: */[
+              2,
+              /* :: */[
+                3,
+                /* :: */[
+                  4,
+                  /* [] */0
+                ]
+              ]
+            ]), "folks", /* :: */[
+          100,
+          /* [] */0
+        ]));
+
+check("File \"js_json_test.ml\", line 402, characters 8-15", /* array */[
+      /* `A */[
+        65,
+        3
+      ],
+      /* `B */[
+        66,
+        2.0
+      ],
+      /* `C */[
+        67,
+        "hi"
+      ]
+    ]);
+
 Mt.from_pair_suites("js_json_test.ml", suites[0]);
 
 exports.suites = suites;
@@ -594,4 +650,5 @@ exports.false_ = false_;
 exports.true_ = true_;
 exports.option_get = option_get;
 exports.eq_at_i = eq_at_i;
+exports.check = check;
 /* v Not a pure module */

jscomp/test/js_json_test.ml

@@ -389,4 +389,16 @@ let () =
   eq __LOC__ 
     (Js.Json.decodeNull (Js.Json.number 1.23)) None
 
+(* serializeAny tests *)
+type aRecord = {a: int; b: float option; c: (string, string) Belt.Result.t; d: aRecord list}
+
+let check loc value = eq loc (Js.Json.unserializeAnyFromJsonUnsafe (Js.Json.serializeAnyToJson value)) value
+
+let () =
+  check __LOC__ {a=2; b=None; c=Ok "folks"; d=[]};
+  check __LOC__ [2,3,4,5];
+  check __LOC__ (`Poly 3);
+  check __LOC__ (Belt.Map.String.empty |. Belt.Map.String.set "hello" [2;3;4] |. Belt.Map.String.set "folks" [100]);
+  check __LOC__ [|`A 3; `B 2.0; `C "hi"|]
+
 let () = Mt.from_pair_suites __FILE__ !suites

lib/js/js_json.js

@@ -88,6 +88,86 @@ function decodeNull(json) {
 
 }
 
+var _toJson = function (data){
+  if (!data) {
+    return data
+  } else if (typeof data === 'function') {
+    throw new Error("Cannot serialize a function")
+  } else if (Array.isArray(data)) {
+    if (data.tag != null) {
+      return {
+        $$tag: data.tag,
+        $$contents: data.map(_toJson),
+        $$bsVariant: data[Symbol.for('BsVariant')],
+      }
+    } else if (data[Symbol.for('BsVariant')] != null) {
+      return {
+        $$bsVariant: data[Symbol.for('BsVariant')],
+        $$contents: data.map(_toJson)
+      }
+    } else if (data[Symbol.for('BsLocalModule')] != null) {
+      return {
+        $$bsLocalModule: data[Symbol.for('BsLocalModule')],
+        $$contents: data.map(_toJson)
+      }
+    } else if (data[Symbol.for('BsPolyVar')] != null) {
+      return {
+        $$bsPolyVar: data[Symbol.for('BsPolyVar')],
+        $$contents: data.map(_toJson)
+      }
+    } else if (data[Symbol.for('BsRecord')] != null) {
+      return {
+        $$bsRecord: data[Symbol.for('BsRecord')],
+        $$contents: data.map(_toJson)
+      }
+    } else {
+      return data.map(_toJson)
+    }
+  } else if (typeof data == 'object') {
+    var result = {}
+    Object.keys(data).forEach(key => result[key] = _toJson(data[key]))
+    return result
+  } else {
+    return data
+  }
+};
+
+var serializeAnyToJson = _toJson;
+
+var unserializeAnyFromJsonUnsafe = function (data){
+  if (!data) {
+    return data
+  } else if (typeof data == 'object') {
+    if (Array.isArray(data)) {
+      return data.map(unserializeAnyFromJsonUnsafe)
+    } else if (data.$$contents) {
+      var result = data.$$contents.map(unserializeAnyFromJsonUnsafe)
+      if (data.$$tag != null) {
+        result.tag = data.$$tag
+      }
+      if (data.$$bsRecord) {
+        result[Symbol.for('BsRecord')] = data.$$bsRecord
+      }
+      if (data.$$bsPolyVar) {
+        result[Symbol.for('BsPolyVar')] = data.$$bsPolyVar
+      }
+      if (data.$$bsVariant) {
+        result[Symbol.for('BsVariant')] = data.$$bsVariant
+      }
+      if (data.$$bsLocalModule) {
+        result[Symbol.for('BsLocalModule')] = data.$$bsLocalModule
+      }
+      return result
+    } else {
+      var result = {}
+      Object.keys(data).forEach(key => result[key] = unserializeAnyFromJsonUnsafe(data[key]))
+      return result
+    }
+  } else {
+    return data
+  }
+};
+
 exports.classify = classify;
 exports.test = test;
 exports.decodeString = decodeString;
@@ -96,4 +176,6 @@ exports.decodeObject = decodeObject;
 exports.decodeArray = decodeArray;
 exports.decodeBoolean = decodeBoolean;
 exports.decodeNull = decodeNull;
+exports.serializeAnyToJson = serializeAnyToJson;
+exports.unserializeAnyFromJsonUnsafe = unserializeAnyFromJsonUnsafe;
 /* No side effect */