internal: extract sinon type checking into own module

lib/sinon/create-stub-instance.js

@@ -1,10 +1,11 @@
 "use strict";
 
 const stub = require("./stub");
+const sinonType = require("./util/core/sinon-type");
 const forEach = require("@sinonjs/commons").prototypes.array.forEach;
 
 function isStub(value) {
-    return value && value.throws && value.returns;
+    return sinonType.get(value) === "stub";
 }
 
 module.exports = function createStubInstance(constructor, overrides) {
@@ -13,7 +14,7 @@ module.exports = function createStubInstance(constructor, overrides) {
     }
 
     const stubInstance = Object.create(constructor.prototype);
-    stubInstance[Symbol.for("SinonType")] = "StubInstance";
+    sinonType.set(stubInstance, "stub-instance");
 
     const stubbedObject = stub(stubInstance);
 

lib/sinon/stub.js

@@ -12,6 +12,7 @@ var spy = require("./spy");
 var extend = require("./util/core/extend");
 var getPropertyDescriptor = require("./util/core/get-property-descriptor");
 var isEsModule = require("./util/core/is-es-module");
+var sinonType = require("./util/core/sinon-type");
 var wrapMethod = require("./util/core/wrap-method");
 var throwOnFalsyObject = require("./throw-on-falsy-object");
 var valueToString = require("@sinonjs/commons").valueToString;
@@ -58,6 +59,8 @@ function createStub(originalFunc) {
         id: `stub#${uuid++}`,
     });
 
+    sinonType.set(proxy, "stub");
+
     return proxy;
 }
 

lib/sinon/util/core/sinon-type.js

@@ -0,0 +1,22 @@
+"use strict";
+
+const sinonTypeSymbolProperty = Symbol("SinonType");
+
+module.exports = {
+    /**
+     * Set the type of a Sinon object to make it possible to identify it later at runtime
+     *
+     * @param {object|Function} object  object/function to set the type on
+     * @param {string} type the named type of the object/function
+     */
+    set(object, type) {
+        Object.defineProperty(object, sinonTypeSymbolProperty, {
+            value: type,
+            configurable: false,
+            enumerable: false,
+        });
+    },
+    get(object) {
+        return object && object[sinonTypeSymbolProperty];
+    },
+};

lib/sinon/util/core/wrap-method.js

@@ -4,6 +4,7 @@
 const noop = () => {};
 var getPropertyDescriptor = require("./get-property-descriptor");
 var extend = require("./extend");
+const sinonType = require("./sinon-type");
 var hasOwnProperty =
     require("@sinonjs/commons").prototypes.object.hasOwnProperty;
 var valueToString = require("@sinonjs/commons").valueToString;
@@ -232,7 +233,7 @@ module.exports = function wrapMethod(object, property, method) {
                 }
             }
         }
-        if (object[Symbol.for("SinonType")] === "StubInstance") {
+        if (sinonType.get(object) === "stub-instance") {
             // this is simply to avoid errors after restoring if something should
             // traverse the object in a cleanup phase, ref #2477
             object[property] = noop;