diff --git a/index.js b/index.js
index 299db2a..343e9d3 100644
--- a/index.js
+++ b/index.js
@@ -117,12 +117,26 @@ async function init(path, opts) {
         })
         cleanupsRegistered = true
     }
-
-    if (await fileExists(path)) {
-        proxy = proxyRecurse(JSON.parse(await readFile(path)))
-    }
-    else {
-        proxy = createProxy({})
+    if(!opts || !opts.dict){
+        if (await fileExists(path)) {
+            proxy = proxyRecurse(JSON.parse(await readFile(path)))
+        }
+        else {
+            proxy = createProxy({})
+        }
+    }else{ // use objects without prototype to avoid keys conflicts with inherited props like 'constructor'
+        if (await fileExists(path)) {
+            const c = JSON.parse(await readFile(path), (k,v) => {
+                if(typeof v === 'object' && v !== null && !Array.isArray(v)){
+                  return Object.assign(Object.create(null),v)
+                }
+                return v
+            })
+            proxy = proxyRecurse(c)
+        }
+        else {
+            proxy = createProxy(Object.create(null))
+        }
     }
 
     periodicSave()
diff --git a/package-lock.json b/package-lock.json
index eb8197f..ebcc4ca 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -1,6 +1,6 @@
 {
   "name": "persistent-json-cache",
-  "version": "0.3.1",
+  "version": "1.0.0",
   "lockfileVersion": 1,
   "requires": true,
   "dependencies": {
@@ -1105,6 +1105,53 @@
         }
       }
     },
+    "@eslint/eslintrc": {
+      "version": "0.3.0",
+      "resolved": "https://registry.npmjs.org/@eslint/eslintrc/-/eslintrc-0.3.0.tgz",
+      "integrity": "sha512-1JTKgrOKAHVivSvOYw+sJOunkBjUOvjqWk1DPja7ZFhIS2mX/4EgTT8M7eTK9jrKhL/FvXXEbQwIs3pg1xp3dg==",
+      "dev": true,
+      "requires": {
+        "ajv": "^6.12.4",
+        "debug": "^4.1.1",
+        "espree": "^7.3.0",
+        "globals": "^12.1.0",
+        "ignore": "^4.0.6",
+        "import-fresh": "^3.2.1",
+        "js-yaml": "^3.13.1",
+        "lodash": "^4.17.20",
+        "minimatch": "^3.0.4",
+        "strip-json-comments": "^3.1.1"
+      },
+      "dependencies": {
+        "globals": {
+          "version": "12.4.0",
+          "resolved": "https://registry.npmjs.org/globals/-/globals-12.4.0.tgz",
+          "integrity": "sha512-BWICuzzDvDoH54NHKCseDanAhE3CeDorgDL5MT6LMXXj2WCnd9UC2szdk4AWLfjdgNBCXLUanXYcpBBKOSWGwg==",
+          "dev": true,
+          "requires": {
+            "type-fest": "^0.8.1"
+          }
+        },
+        "ignore": {
+          "version": "4.0.6",
+          "resolved": "https://registry.npmjs.org/ignore/-/ignore-4.0.6.tgz",
+          "integrity": "sha512-cyFDKrqc/YdcWFniJhzI42+AzS+gNwmUzOSFcRCQYwySuBBBy/KjuxWLZ/FHEH6Moq1NizMOBWyTcv8O4OZIMg==",
+          "dev": true
+        },
+        "strip-json-comments": {
+          "version": "3.1.1",
+          "resolved": "https://registry.npmjs.org/strip-json-comments/-/strip-json-comments-3.1.1.tgz",
+          "integrity": "sha512-6fPc+R4ihwqP6N/aIv2f1gMH8lOVtWQHoqC4yK6oSDVVocumAsfCqjkXnqiYMhmMwS/mEHLp7Vehlt3ql6lEig==",
+          "dev": true
+        },
+        "type-fest": {
+          "version": "0.8.1",
+          "resolved": "https://registry.npmjs.org/type-fest/-/type-fest-0.8.1.tgz",
+          "integrity": "sha512-4dbzIzqvjtgiM5rw1k5rEHtBANKmdudhGyBEajN01fEyhaAIhsoKNy6y7+IN93IfpFtwY9iqi7kD+xwKhQsNJA==",
+          "dev": true
+        }
+      }
+    },
     "@nodelib/fs.scandir": {
       "version": "2.1.3",
       "resolved": "https://registry.npmjs.org/@nodelib/fs.scandir/-/fs.scandir-2.1.3.tgz",
@@ -1158,6 +1205,12 @@
       "integrity": "sha512-XNP0PqF1XD19ZlLKvB7cMmnZswW4C/03pRHgirB30uSJTaS3A3V1/P4sS3HPvFmjoriPCJQs+JDSbm4bL1TxGQ==",
       "dev": true
     },
+    "acorn-jsx": {
+      "version": "5.3.1",
+      "resolved": "https://registry.npmjs.org/acorn-jsx/-/acorn-jsx-5.3.1.tgz",
+      "integrity": "sha512-K0Ptm/47OKfQRpNQ2J/oIN/3QYiK6FwW+eJbILhsdxh2WTLdl+30o8aGdTbm5JbffpFFAg/g+zi1E+jvJha5ng==",
+      "dev": true
+    },
     "acorn-walk": {
       "version": "8.0.0",
       "resolved": "https://registry.npmjs.org/acorn-walk/-/acorn-walk-8.0.0.tgz",
@@ -1174,6 +1227,18 @@
         "indent-string": "^4.0.0"
       }
     },
+    "ajv": {
+      "version": "6.12.6",
+      "resolved": "https://registry.npmjs.org/ajv/-/ajv-6.12.6.tgz",
+      "integrity": "sha512-j3fVLgvTo527anyYyJOGTYJbG+vnnQYvE0m5mmkc1TK+nxAppkCLMIL0aZ4dblVCNoGShhm+kzE4ZUykBoMg4g==",
+      "dev": true,
+      "requires": {
+        "fast-deep-equal": "^3.1.1",
+        "fast-json-stable-stringify": "^2.0.0",
+        "json-schema-traverse": "^0.4.1",
+        "uri-js": "^4.2.2"
+      }
+    },
     "ansi-align": {
       "version": "3.0.0",
       "resolved": "https://registry.npmjs.org/ansi-align/-/ansi-align-3.0.0.tgz",
@@ -1223,6 +1288,12 @@
         }
       }
     },
+    "ansi-colors": {
+      "version": "4.1.1",
+      "resolved": "https://registry.npmjs.org/ansi-colors/-/ansi-colors-4.1.1.tgz",
+      "integrity": "sha512-JoX0apGbHaUJBNl6yF+p6JAFYZ666/hhCGKN5t9QFjbJQKUU/g8MNbFDbvfrgKXvI1QpZplPOnwIo99lX/AAmA==",
+      "dev": true
+    },
     "ansi-regex": {
       "version": "5.0.0",
       "resolved": "https://registry.npmjs.org/ansi-regex/-/ansi-regex-5.0.0.tgz",
@@ -1734,6 +1805,17 @@
         }
       }
     },
+    "cross-spawn": {
+      "version": "7.0.3",
+      "resolved": "https://registry.npmjs.org/cross-spawn/-/cross-spawn-7.0.3.tgz",
+      "integrity": "sha512-iRDPJKUPVEND7dHPO8rkbOnPpyDygcDFtWjpeWNCgy8WP2rXcxXL8TskReQl6OrB2G7+UJrags1q15Fudc7G6w==",
+      "dev": true,
+      "requires": {
+        "path-key": "^3.1.0",
+        "shebang-command": "^2.0.0",
+        "which": "^2.0.1"
+      }
+    },
     "crypto-random-string": {
       "version": "2.0.0",
       "resolved": "https://registry.npmjs.org/crypto-random-string/-/crypto-random-string-2.0.0.tgz",
@@ -1782,6 +1864,12 @@
       "integrity": "sha512-LOHxIOaPYdHlJRtCQfDIVZtfw/ufM8+rVj649RIHzcm/vGwQRXFt6OPqIFWsm2XEMrNIEtWR64sY1LEKD2vAOA==",
       "dev": true
     },
+    "deep-is": {
+      "version": "0.1.3",
+      "resolved": "https://registry.npmjs.org/deep-is/-/deep-is-0.1.3.tgz",
+      "integrity": "sha1-s2nW+128E+7PUk+RsHD+7cNXzzQ=",
+      "dev": true
+    },
     "defaults": {
       "version": "1.0.3",
       "resolved": "https://registry.npmjs.org/defaults/-/defaults-1.0.3.tgz",
@@ -1831,6 +1919,15 @@
         "path-type": "^4.0.0"
       }
     },
+    "doctrine": {
+      "version": "3.0.0",
+      "resolved": "https://registry.npmjs.org/doctrine/-/doctrine-3.0.0.tgz",
+      "integrity": "sha512-yS+Q5i3hBf7GBkd4KG8a7eBNNWNGLTaEwwYWUijIYM7zrlYDM0BFXHjjPWlWZ1Rg7UaddZeIDmi9jF3HmqiQ2w==",
+      "dev": true,
+      "requires": {
+        "esutils": "^2.0.2"
+      }
+    },
     "dot-prop": {
       "version": "5.3.0",
       "resolved": "https://registry.npmjs.org/dot-prop/-/dot-prop-5.3.0.tgz",
@@ -1873,6 +1970,15 @@
         "once": "^1.4.0"
       }
     },
+    "enquirer": {
+      "version": "2.3.6",
+      "resolved": "https://registry.npmjs.org/enquirer/-/enquirer-2.3.6.tgz",
+      "integrity": "sha512-yjNnPr315/FjS4zIsUxYguYUPP2e1NK4d7E7ZOLiyYCcbFBiTMyID+2wvm2w6+pZ/odMA7cRkjhsPbltwBOrLg==",
+      "dev": true,
+      "requires": {
+        "ansi-colors": "^4.1.1"
+      }
+    },
     "equal-length": {
       "version": "1.0.1",
       "resolved": "https://registry.npmjs.org/equal-length/-/equal-length-1.0.1.tgz",
@@ -1906,18 +2012,205 @@
       "integrity": "sha1-G2HAViGQqN/2rjuyzwIAyhMLhtQ=",
       "dev": true
     },
+    "eslint": {
+      "version": "7.20.0",
+      "resolved": "https://registry.npmjs.org/eslint/-/eslint-7.20.0.tgz",
+      "integrity": "sha512-qGi0CTcOGP2OtCQBgWZlQjcTuP0XkIpYFj25XtRTQSHC+umNnp7UMshr2G8SLsRFYDdAPFeHOsiteadmMH02Yw==",
+      "dev": true,
+      "requires": {
+        "@babel/code-frame": "7.12.11",
+        "@eslint/eslintrc": "^0.3.0",
+        "ajv": "^6.10.0",
+        "chalk": "^4.0.0",
+        "cross-spawn": "^7.0.2",
+        "debug": "^4.0.1",
+        "doctrine": "^3.0.0",
+        "enquirer": "^2.3.5",
+        "eslint-scope": "^5.1.1",
+        "eslint-utils": "^2.1.0",
+        "eslint-visitor-keys": "^2.0.0",
+        "espree": "^7.3.1",
+        "esquery": "^1.4.0",
+        "esutils": "^2.0.2",
+        "file-entry-cache": "^6.0.0",
+        "functional-red-black-tree": "^1.0.1",
+        "glob-parent": "^5.0.0",
+        "globals": "^12.1.0",
+        "ignore": "^4.0.6",
+        "import-fresh": "^3.0.0",
+        "imurmurhash": "^0.1.4",
+        "is-glob": "^4.0.0",
+        "js-yaml": "^3.13.1",
+        "json-stable-stringify-without-jsonify": "^1.0.1",
+        "levn": "^0.4.1",
+        "lodash": "^4.17.20",
+        "minimatch": "^3.0.4",
+        "natural-compare": "^1.4.0",
+        "optionator": "^0.9.1",
+        "progress": "^2.0.0",
+        "regexpp": "^3.1.0",
+        "semver": "^7.2.1",
+        "strip-ansi": "^6.0.0",
+        "strip-json-comments": "^3.1.0",
+        "table": "^6.0.4",
+        "text-table": "^0.2.0",
+        "v8-compile-cache": "^2.0.3"
+      },
+      "dependencies": {
+        "@babel/code-frame": {
+          "version": "7.12.11",
+          "resolved": "https://registry.npmjs.org/@babel/code-frame/-/code-frame-7.12.11.tgz",
+          "integrity": "sha512-Zt1yodBx1UcyiePMSkWnU4hPqhwq7hGi2nFL1LeA3EUl+q2LQx16MISgJ0+z7dnmgvP9QtIleuETGOiOH1RcIw==",
+          "dev": true,
+          "requires": {
+            "@babel/highlight": "^7.10.4"
+          }
+        },
+        "globals": {
+          "version": "12.4.0",
+          "resolved": "https://registry.npmjs.org/globals/-/globals-12.4.0.tgz",
+          "integrity": "sha512-BWICuzzDvDoH54NHKCseDanAhE3CeDorgDL5MT6LMXXj2WCnd9UC2szdk4AWLfjdgNBCXLUanXYcpBBKOSWGwg==",
+          "dev": true,
+          "requires": {
+            "type-fest": "^0.8.1"
+          }
+        },
+        "ignore": {
+          "version": "4.0.6",
+          "resolved": "https://registry.npmjs.org/ignore/-/ignore-4.0.6.tgz",
+          "integrity": "sha512-cyFDKrqc/YdcWFniJhzI42+AzS+gNwmUzOSFcRCQYwySuBBBy/KjuxWLZ/FHEH6Moq1NizMOBWyTcv8O4OZIMg==",
+          "dev": true
+        },
+        "strip-json-comments": {
+          "version": "3.1.1",
+          "resolved": "https://registry.npmjs.org/strip-json-comments/-/strip-json-comments-3.1.1.tgz",
+          "integrity": "sha512-6fPc+R4ihwqP6N/aIv2f1gMH8lOVtWQHoqC4yK6oSDVVocumAsfCqjkXnqiYMhmMwS/mEHLp7Vehlt3ql6lEig==",
+          "dev": true
+        },
+        "type-fest": {
+          "version": "0.8.1",
+          "resolved": "https://registry.npmjs.org/type-fest/-/type-fest-0.8.1.tgz",
+          "integrity": "sha512-4dbzIzqvjtgiM5rw1k5rEHtBANKmdudhGyBEajN01fEyhaAIhsoKNy6y7+IN93IfpFtwY9iqi7kD+xwKhQsNJA==",
+          "dev": true
+        }
+      }
+    },
+    "eslint-scope": {
+      "version": "5.1.1",
+      "resolved": "https://registry.npmjs.org/eslint-scope/-/eslint-scope-5.1.1.tgz",
+      "integrity": "sha512-2NxwbF/hZ0KpepYN0cNbo+FN6XoK7GaHlQhgx/hIZl6Va0bF45RQOOwhLIy8lQDbuCiadSLCBnH2CFYquit5bw==",
+      "dev": true,
+      "requires": {
+        "esrecurse": "^4.3.0",
+        "estraverse": "^4.1.1"
+      }
+    },
+    "eslint-utils": {
+      "version": "2.1.0",
+      "resolved": "https://registry.npmjs.org/eslint-utils/-/eslint-utils-2.1.0.tgz",
+      "integrity": "sha512-w94dQYoauyvlDc43XnGB8lU3Zt713vNChgt4EWwhXAP2XkBvndfxF0AgIqKOOasjPIPzj9JqgwkwbCYD0/V3Zg==",
+      "dev": true,
+      "requires": {
+        "eslint-visitor-keys": "^1.1.0"
+      },
+      "dependencies": {
+        "eslint-visitor-keys": {
+          "version": "1.3.0",
+          "resolved": "https://registry.npmjs.org/eslint-visitor-keys/-/eslint-visitor-keys-1.3.0.tgz",
+          "integrity": "sha512-6J72N8UNa462wa/KFODt/PJ3IU60SDpC3QXC1Hjc1BXXpfL2C9R5+AU7jhe0F6GREqVMh4Juu+NY7xn+6dipUQ==",
+          "dev": true
+        }
+      }
+    },
+    "eslint-visitor-keys": {
+      "version": "2.0.0",
+      "resolved": "https://registry.npmjs.org/eslint-visitor-keys/-/eslint-visitor-keys-2.0.0.tgz",
+      "integrity": "sha512-QudtT6av5WXels9WjIM7qz1XD1cWGvX4gGXvp/zBn9nXG02D0utdU3Em2m/QjTnrsk6bBjmCygl3rmj118msQQ==",
+      "dev": true
+    },
+    "espree": {
+      "version": "7.3.1",
+      "resolved": "https://registry.npmjs.org/espree/-/espree-7.3.1.tgz",
+      "integrity": "sha512-v3JCNCE64umkFpmkFGqzVKsOT0tN1Zr+ueqLZfpV1Ob8e+CEgPWa+OxCoGH3tnhimMKIaBm4m/vaRpJ/krRz2g==",
+      "dev": true,
+      "requires": {
+        "acorn": "^7.4.0",
+        "acorn-jsx": "^5.3.1",
+        "eslint-visitor-keys": "^1.3.0"
+      },
+      "dependencies": {
+        "acorn": {
+          "version": "7.4.1",
+          "resolved": "https://registry.npmjs.org/acorn/-/acorn-7.4.1.tgz",
+          "integrity": "sha512-nQyp0o1/mNdbTO1PO6kHkwSrmgZ0MT/jCCpNiwbUjGoRN4dlBhqJtoQuCnEOKzgTVwg0ZWiCoQy6SxMebQVh8A==",
+          "dev": true
+        },
+        "eslint-visitor-keys": {
+          "version": "1.3.0",
+          "resolved": "https://registry.npmjs.org/eslint-visitor-keys/-/eslint-visitor-keys-1.3.0.tgz",
+          "integrity": "sha512-6J72N8UNa462wa/KFODt/PJ3IU60SDpC3QXC1Hjc1BXXpfL2C9R5+AU7jhe0F6GREqVMh4Juu+NY7xn+6dipUQ==",
+          "dev": true
+        }
+      }
+    },
     "esprima": {
       "version": "4.0.1",
       "resolved": "https://registry.npmjs.org/esprima/-/esprima-4.0.1.tgz",
       "integrity": "sha512-eGuFFw7Upda+g4p+QHvnW0RyTX/SVeJBDM/gCtMARO0cLuT2HcEKnTPvhjV6aGeqrCB/sbNop0Kszm0jsaWU4A==",
       "dev": true
     },
+    "esquery": {
+      "version": "1.4.0",
+      "resolved": "https://registry.npmjs.org/esquery/-/esquery-1.4.0.tgz",
+      "integrity": "sha512-cCDispWt5vHHtwMY2YrAQ4ibFkAL8RbH5YGBnZBc90MolvvfkkQcJro/aZiAQUlQ3qgrYS6D6v8Gc5G5CQsc9w==",
+      "dev": true,
+      "requires": {
+        "estraverse": "^5.1.0"
+      },
+      "dependencies": {
+        "estraverse": {
+          "version": "5.2.0",
+          "resolved": "https://registry.npmjs.org/estraverse/-/estraverse-5.2.0.tgz",
+          "integrity": "sha512-BxbNGGNm0RyRYvUdHpIwv9IWzeM9XClbOxwoATuFdOE7ZE6wHL+HQ5T8hoPM+zHvmKzzsEqhgy0GrQ5X13afiQ==",
+          "dev": true
+        }
+      }
+    },
+    "esrecurse": {
+      "version": "4.3.0",
+      "resolved": "https://registry.npmjs.org/esrecurse/-/esrecurse-4.3.0.tgz",
+      "integrity": "sha512-KmfKL3b6G+RXvP8N1vr3Tq1kL/oCFgn2NYXEtqP8/L3pKapUA4G8cFVaoF3SU323CD4XypR/ffioHmkti6/Tag==",
+      "dev": true,
+      "requires": {
+        "estraverse": "^5.2.0"
+      },
+      "dependencies": {
+        "estraverse": {
+          "version": "5.2.0",
+          "resolved": "https://registry.npmjs.org/estraverse/-/estraverse-5.2.0.tgz",
+          "integrity": "sha512-BxbNGGNm0RyRYvUdHpIwv9IWzeM9XClbOxwoATuFdOE7ZE6wHL+HQ5T8hoPM+zHvmKzzsEqhgy0GrQ5X13afiQ==",
+          "dev": true
+        }
+      }
+    },
+    "estraverse": {
+      "version": "4.3.0",
+      "resolved": "https://registry.npmjs.org/estraverse/-/estraverse-4.3.0.tgz",
+      "integrity": "sha512-39nnKffWz8xN1BU/2c79n9nB9HDzo0niYUqx6xyqUnyoAnQyyWpOTdZEeiCch8BBu515t4wp9ZmgVfVhn9EBpw==",
+      "dev": true
+    },
     "esutils": {
       "version": "2.0.3",
       "resolved": "https://registry.npmjs.org/esutils/-/esutils-2.0.3.tgz",
       "integrity": "sha512-kVscqXk4OCp68SZ0dkgEKVi6/8ij300KBWTJq32P/dYeWTSwK41WyTxalN1eRmA5Z9UU/LX9D7FWSmV9SAYx6g==",
       "dev": true
     },
+    "fast-deep-equal": {
+      "version": "3.1.3",
+      "resolved": "https://registry.npmjs.org/fast-deep-equal/-/fast-deep-equal-3.1.3.tgz",
+      "integrity": "sha512-f3qQ9oQy9j2AhBe/H9VC91wLmKBCCU/gDOnKNAYG5hswO7BLKj09Hc5HYNz9cGI++xlpDCIgDaitVs03ATR84Q==",
+      "dev": true
+    },
     "fast-diff": {
       "version": "1.2.0",
       "resolved": "https://registry.npmjs.org/fast-diff/-/fast-diff-1.2.0.tgz",
@@ -1938,6 +2231,18 @@
         "picomatch": "^2.2.1"
       }
     },
+    "fast-json-stable-stringify": {
+      "version": "2.1.0",
+      "resolved": "https://registry.npmjs.org/fast-json-stable-stringify/-/fast-json-stable-stringify-2.1.0.tgz",
+      "integrity": "sha512-lhd/wF+Lk98HZoTCtlVraHtfh5XYijIjalXck7saUtuanSDyLMxnHhSXEDJqHxD7msR8D0uCmqlkwjCV8xvwHw==",
+      "dev": true
+    },
+    "fast-levenshtein": {
+      "version": "2.0.6",
+      "resolved": "https://registry.npmjs.org/fast-levenshtein/-/fast-levenshtein-2.0.6.tgz",
+      "integrity": "sha1-PYpcZog6FqMMqGQ+hR8Zuqd5eRc=",
+      "dev": true
+    },
     "fastq": {
       "version": "1.9.0",
       "resolved": "https://registry.npmjs.org/fastq/-/fastq-1.9.0.tgz",
@@ -1956,6 +2261,15 @@
         "escape-string-regexp": "^1.0.5"
       }
     },
+    "file-entry-cache": {
+      "version": "6.0.1",
+      "resolved": "https://registry.npmjs.org/file-entry-cache/-/file-entry-cache-6.0.1.tgz",
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@@ -1975,6 +2289,22 @@
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+        "rimraf": "^3.0.2"
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+      "resolved": "https://registry.npmjs.org/import-fresh/-/import-fresh-3.3.0.tgz",
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+        "resolve-from": "^4.0.0"
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+          "resolved": "https://registry.npmjs.org/resolve-from/-/resolve-from-4.0.0.tgz",
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+          "dev": true
+        }
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+    },
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+      "resolved": "https://registry.npmjs.org/isexe/-/isexe-2.0.0.tgz",
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       "dev": true
     },
+    "json-schema-traverse": {
+      "version": "0.4.1",
+      "resolved": "https://registry.npmjs.org/json-schema-traverse/-/json-schema-traverse-0.4.1.tgz",
+      "integrity": "sha512-xbbCH5dCYU5T8LcEhhuh7HJ88HXuW3qsI3Y0zOZFKfZEHcpWiHU/Jxzk629Brsab/mMiHQti9wMP+845RPe3Vg==",
+      "dev": true
+    },
+    "json-stable-stringify-without-jsonify": {
+      "version": "1.0.1",
+      "resolved": "https://registry.npmjs.org/json-stable-stringify-without-jsonify/-/json-stable-stringify-without-jsonify-1.0.1.tgz",
+      "integrity": "sha1-nbe1lJatPzz+8wp1FC0tkwrXJlE=",
+      "dev": true
+    },
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@@ -2413,6 +2785,16 @@
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       }
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+    "levn": {
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+      "resolved": "https://registry.npmjs.org/levn/-/levn-0.4.1.tgz",
+      "integrity": "sha512-+bT2uH4E5LGE7h/n3evcS/sQlJXCpIp6ym8OWJ5eV6+67Dsql/LaaT7qJBAt2rzfoa/5QBGBhxDix1dMt2kQKQ==",
+      "dev": true,
+      "requires": {
+        "prelude-ls": "^1.2.1",
+        "type-check": "~0.4.0"
+      }
+    },
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       "resolved": "https://registry.npmjs.org/lines-and-columns/-/lines-and-columns-1.1.6.tgz",
@@ -2652,6 +3034,12 @@
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       "dev": true
     },
+    "natural-compare": {
+      "version": "1.4.0",
+      "resolved": "https://registry.npmjs.org/natural-compare/-/natural-compare-1.4.0.tgz",
+      "integrity": "sha1-Sr6/7tdUHywnrPspvbvRXI1bpPc=",
+      "dev": true
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       "resolved": "https://registry.npmjs.org/node-releases/-/node-releases-1.1.67.tgz",
@@ -2726,6 +3114,20 @@
         "mimic-fn": "^2.1.0"
       }
     },
+    "optionator": {
+      "version": "0.9.1",
+      "resolved": "https://registry.npmjs.org/optionator/-/optionator-0.9.1.tgz",
+      "integrity": "sha512-74RlY5FCnhq4jRxVUPKDaRwrVNXMqsGsiW6AJw4XK8hmtm10wC0ypZBLw5IIp85NZMr91+qd1RvvENwg7jjRFw==",
+      "dev": true,
+      "requires": {
+        "deep-is": "^0.1.3",
+        "fast-levenshtein": "^2.0.6",
+        "levn": "^0.4.1",
+        "prelude-ls": "^1.2.1",
+        "type-check": "^0.4.0",
+        "word-wrap": "^1.2.3"
+      }
+    },
     "ora": {
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       "resolved": "https://registry.npmjs.org/ora/-/ora-5.1.0.tgz",
@@ -2831,6 +3233,15 @@
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       }
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+    "parent-module": {
+      "version": "1.0.1",
+      "resolved": "https://registry.npmjs.org/parent-module/-/parent-module-1.0.1.tgz",
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+      "dev": true,
+      "requires": {
+        "callsites": "^3.0.0"
+      }
+    },
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       "resolved": "https://registry.npmjs.org/parse-json/-/parse-json-4.0.0.tgz",
@@ -2859,6 +3270,12 @@
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       "dev": true
     },
+    "path-key": {
+      "version": "3.1.1",
+      "resolved": "https://registry.npmjs.org/path-key/-/path-key-3.1.1.tgz",
+      "integrity": "sha512-ojmeN0qd+y0jszEtoY48r0Peq5dwMEkIlCOu6Q5f41lfkswXuKtYrhgoTpLnyIcHm24Uhqx+5Tqm2InSwLhE6Q==",
+      "dev": true
+    },
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       "version": "1.0.6",
       "resolved": "https://registry.npmjs.org/path-parse/-/path-parse-1.0.6.tgz",
@@ -2947,6 +3364,12 @@
         "irregular-plurals": "^3.2.0"
       }
     },
+    "prelude-ls": {
+      "version": "1.2.1",
+      "resolved": "https://registry.npmjs.org/prelude-ls/-/prelude-ls-1.2.1.tgz",
+      "integrity": "sha512-vkcDPrRZo1QZLbn5RLGPpg/WmIQ65qoWWhcGKf/b5eplkkarX0m9z8ppCat4mlOqUsWpyNuYgO3VRyrYHSzX5g==",
+      "dev": true
+    },
     "prepend-http": {
       "version": "2.0.0",
       "resolved": "https://registry.npmjs.org/prepend-http/-/prepend-http-2.0.0.tgz",
@@ -2962,6 +3385,12 @@
         "parse-ms": "^2.1.0"
       }
     },
+    "progress": {
+      "version": "2.0.3",
+      "resolved": "https://registry.npmjs.org/progress/-/progress-2.0.3.tgz",
+      "integrity": "sha512-7PiHtLll5LdnKIMw100I+8xJXR5gW2QwWYkT6iJva0bXitZKa/XMrSbdmg3r2Xnaidz9Qumd0VPaMrZlF9V9sA==",
+      "dev": true
+    },
     "pump": {
       "version": "3.0.0",
       "resolved": "https://registry.npmjs.org/pump/-/pump-3.0.0.tgz",
@@ -2972,6 +3401,12 @@
         "once": "^1.3.1"
       }
     },
+    "punycode": {
+      "version": "2.1.1",
+      "resolved": "https://registry.npmjs.org/punycode/-/punycode-2.1.1.tgz",
+      "integrity": "sha512-XRsRjdf+j5ml+y/6GKHPZbrF/8p2Yga0JPtdqTIY2Xe5ohJPD9saDJJLPvp9+NSBprVvevdXZybnj2cv8OEd0A==",
+      "dev": true
+    },
     "pupa": {
       "version": "2.1.1",
       "resolved": "https://registry.npmjs.org/pupa/-/pupa-2.1.1.tgz",
@@ -3064,6 +3499,12 @@
         "@babel/runtime": "^7.8.4"
       }
     },
+    "regexpp": {
+      "version": "3.1.0",
+      "resolved": "https://registry.npmjs.org/regexpp/-/regexpp-3.1.0.tgz",
+      "integrity": "sha512-ZOIzd8yVsQQA7j8GCSlPGXwg5PfmA1mrq0JP4nGhh54LaKN3xdai/vHUDu74pKwV8OxseMS65u2NImosQcSD0Q==",
+      "dev": true
+    },
     "regexpu-core": {
       "version": "4.7.1",
       "resolved": "https://registry.npmjs.org/regexpu-core/-/regexpu-core-4.7.1.tgz",
@@ -3125,6 +3566,12 @@
       "integrity": "sha1-jGStX9MNqxyXbiNE/+f3kqam30I=",
       "dev": true
     },
+    "require-from-string": {
+      "version": "2.0.2",
+      "resolved": "https://registry.npmjs.org/require-from-string/-/require-from-string-2.0.2.tgz",
+      "integrity": "sha512-Xf0nWe6RseziFMu+Ap9biiUbmplq6S9/p+7w7YXP/JBHhrUDDUhwa+vANyubuqfZWTveU//DYVGsDG7RKL/vEw==",
+      "dev": true
+    },
     "resolve": {
       "version": "1.19.0",
       "resolved": "https://registry.npmjs.org/resolve/-/resolve-1.19.0.tgz",
@@ -3225,6 +3672,21 @@
       "integrity": "sha1-ULZ51WNc34Rme9yOWa9OW4HV9go=",
       "dev": true
     },
+    "shebang-command": {
+      "version": "2.0.0",
+      "resolved": "https://registry.npmjs.org/shebang-command/-/shebang-command-2.0.0.tgz",
+      "integrity": "sha512-kHxr2zZpYtdmrN1qDjrrX/Z1rR1kG8Dx+gkpK1G4eXmvXswmcE1hTWBWYUzlraYw1/yZp6YuDY77YtvbN0dmDA==",
+      "dev": true,
+      "requires": {
+        "shebang-regex": "^3.0.0"
+      }
+    },
+    "shebang-regex": {
+      "version": "3.0.0",
+      "resolved": "https://registry.npmjs.org/shebang-regex/-/shebang-regex-3.0.0.tgz",
+      "integrity": "sha512-7++dFhtcx3353uBaq8DDR4NuxBetBzC7ZQOhmTQInHEd6bSrXdiEyzCvG07Z44UYdLShWUyXt5M/yhz8ekcb1A==",
+      "dev": true
+    },
     "signal-exit": {
       "version": "3.0.3",
       "resolved": "https://registry.npmjs.org/signal-exit/-/signal-exit-3.0.3.tgz",
@@ -3402,6 +3864,49 @@
         "has-flag": "^4.0.0"
       }
     },
+    "table": {
+      "version": "6.0.7",
+      "resolved": "https://registry.npmjs.org/table/-/table-6.0.7.tgz",
+      "integrity": "sha512-rxZevLGTUzWna/qBLObOe16kB2RTnnbhciwgPbMMlazz1yZGVEgnZK762xyVdVznhqxrfCeBMmMkgOOaPwjH7g==",
+      "dev": true,
+      "requires": {
+        "ajv": "^7.0.2",
+        "lodash": "^4.17.20",
+        "slice-ansi": "^4.0.0",
+        "string-width": "^4.2.0"
+      },
+      "dependencies": {
+        "ajv": {
+          "version": "7.1.1",
+          "resolved": "https://registry.npmjs.org/ajv/-/ajv-7.1.1.tgz",
+          "integrity": "sha512-ga/aqDYnUy/o7vbsRTFhhTsNeXiYb5JWDIcRIeZfwRNCefwjNTVYCGdGSUrEmiu3yDK3vFvNbgJxvrQW4JXrYQ==",
+          "dev": true,
+          "requires": {
+            "fast-deep-equal": "^3.1.1",
+            "json-schema-traverse": "^1.0.0",
+            "require-from-string": "^2.0.2",
+            "uri-js": "^4.2.2"
+          }
+        },
+        "json-schema-traverse": {
+          "version": "1.0.0",
+          "resolved": "https://registry.npmjs.org/json-schema-traverse/-/json-schema-traverse-1.0.0.tgz",
+          "integrity": "sha512-NM8/P9n3XjXhIZn1lLhkFaACTOURQXjWhV4BA/RnOv8xvgqtqpAX9IO4mRQxSx1Rlo4tqzeqb0sOlruaOy3dug==",
+          "dev": true
+        },
+        "slice-ansi": {
+          "version": "4.0.0",
+          "resolved": "https://registry.npmjs.org/slice-ansi/-/slice-ansi-4.0.0.tgz",
+          "integrity": "sha512-qMCMfhY040cVHT43K9BFygqYbUPFZKHOg7K73mtTWJRb8pyP3fzf4Ixd5SzdEJQ6MRUg/WBnOLxghZtKKurENQ==",
+          "dev": true,
+          "requires": {
+            "ansi-styles": "^4.0.0",
+            "astral-regex": "^2.0.0",
+            "is-fullwidth-code-point": "^3.0.0"
+          }
+        }
+      }
+    },
     "temp-dir": {
       "version": "2.0.0",
       "resolved": "https://registry.npmjs.org/temp-dir/-/temp-dir-2.0.0.tgz",
@@ -3414,6 +3919,12 @@
       "integrity": "sha512-wK0Ri4fOGjv/XPy8SBHZChl8CM7uMc5VML7SqiQ0zG7+J5Vr+RMQDoHa2CNT6KHUnTGIXH34UDMkPzAUyapBZg==",
       "dev": true
     },
+    "text-table": {
+      "version": "0.2.0",
+      "resolved": "https://registry.npmjs.org/text-table/-/text-table-0.2.0.tgz",
+      "integrity": "sha1-f17oI66AUgfACvLfSoTsP8+lcLQ=",
+      "dev": true
+    },
     "time-zone": {
       "version": "1.0.0",
       "resolved": "https://registry.npmjs.org/time-zone/-/time-zone-1.0.0.tgz",
@@ -3447,6 +3958,15 @@
       "integrity": "sha1-n5up2e+odkw4dpi8v+sshI8RrbM=",
       "dev": true
     },
+    "type-check": {
+      "version": "0.4.0",
+      "resolved": "https://registry.npmjs.org/type-check/-/type-check-0.4.0.tgz",
+      "integrity": "sha512-XleUoc9uwGXqjWwXaUTZAmzMcFZ5858QA2vvx1Ur5xIcixXIP+8LnFDgRplU30us6teqdlskFfu+ae4K79Ooew==",
+      "dev": true,
+      "requires": {
+        "prelude-ls": "^1.2.1"
+      }
+    },
     "type-fest": {
       "version": "0.3.1",
       "resolved": "https://registry.npmjs.org/type-fest/-/type-fest-0.3.1.tgz",
@@ -3532,6 +4052,15 @@
         }
       }
     },
+    "uri-js": {
+      "version": "4.4.1",
+      "resolved": "https://registry.npmjs.org/uri-js/-/uri-js-4.4.1.tgz",
+      "integrity": "sha512-7rKUyy33Q1yc98pQ1DAmLtwX109F7TIfWlW1Ydo8Wl1ii1SeHieeh0HHfPeL2fMXK6z0s8ecKs9frCuLJvndBg==",
+      "dev": true,
+      "requires": {
+        "punycode": "^2.1.0"
+      }
+    },
     "url-parse-lax": {
       "version": "3.0.0",
       "resolved": "https://registry.npmjs.org/url-parse-lax/-/url-parse-lax-3.0.0.tgz",
@@ -3541,6 +4070,12 @@
         "prepend-http": "^2.0.0"
       }
     },
+    "v8-compile-cache": {
+      "version": "2.2.0",
+      "resolved": "https://registry.npmjs.org/v8-compile-cache/-/v8-compile-cache-2.2.0.tgz",
+      "integrity": "sha512-gTpR5XQNKFwOd4clxfnhaqvfqMpqEwr4tOtCyz4MtYZX2JYhfr1JvBFKdS+7K/9rfpZR3VLX+YWBbKoxCgS43Q==",
+      "dev": true
+    },
     "validate-npm-package-license": {
       "version": "3.0.4",
       "resolved": "https://registry.npmjs.org/validate-npm-package-license/-/validate-npm-package-license-3.0.4.tgz",
@@ -3566,6 +4101,15 @@
       "integrity": "sha512-ZMjC3ho+KXo0BfJb7JgtQ5IBuvnShdlACNkKkdsqBmYw3bPAaJfPeYUo6tLUaT5tG/Gkh7xkpBhKRQ9e7pyg9Q==",
       "dev": true
     },
+    "which": {
+      "version": "2.0.2",
+      "resolved": "https://registry.npmjs.org/which/-/which-2.0.2.tgz",
+      "integrity": "sha512-BLI3Tl1TW3Pvl70l3yq3Y64i+awpwXqsGBYWkkqMtnbXgrMD+yj7rhW0kuEDxzJaYXGjEW5ogapKNMEKNMjibA==",
+      "dev": true,
+      "requires": {
+        "isexe": "^2.0.0"
+      }
+    },
     "widest-line": {
       "version": "3.1.0",
       "resolved": "https://registry.npmjs.org/widest-line/-/widest-line-3.1.0.tgz",
@@ -3575,6 +4119,12 @@
         "string-width": "^4.0.0"
       }
     },
+    "word-wrap": {
+      "version": "1.2.3",
+      "resolved": "https://registry.npmjs.org/word-wrap/-/word-wrap-1.2.3.tgz",
+      "integrity": "sha512-Hz/mrNwitNRh/HUAtM/VT/5VH+ygD6DV7mYKZAtHOrbs8U7lvPS6xf7EJKMF0uW1KJCl0H701g3ZGus+muE5vQ==",
+      "dev": true
+    },
     "wrap-ansi": {
       "version": "7.0.0",
       "resolved": "https://registry.npmjs.org/wrap-ansi/-/wrap-ansi-7.0.0.tgz",
diff --git a/package.json b/package.json
index 5d28565..93e48d8 100644
--- a/package.json
+++ b/package.json
@@ -9,11 +9,12 @@
   "main": "index.js",
   "devDependencies": {
     "ava": "^3.13.0",
+    "eslint": "^7.20.0",
     "markdown-doctest": "^1.1.0"
   },
   "scripts": {
     "doctest": "node --unhandled-rejections=strict node_modules/.bin/markdown-doctest",
-    "test": "ava"
+    "test": "ava && eslint index.js && eslint tests/** "
   },
   "keywords": [
     "transparent",
diff --git a/tests/test.js b/tests/test.js
index 08b2e35..5829c35 100644
--- a/tests/test.js
+++ b/tests/test.js
@@ -3,6 +3,8 @@ const fs = require('fs/promises')
 const os = require('os')
 const path = require('path')
 const test = require('ava')
+const reservedKeys1 = ['constructor', 'hasOwnProperty', 'isPrototypeOf', 'propertyIsEnumerable', 'toLocaleString', 'toString', 'valueOf'];
+const reservedKeys2 = ['__defineGetter__', '__defineSetter__', '__lookupGetter__', '__lookupSetter__', '__proto__'];
 
 const persistent = require('../index')
 
@@ -189,3 +191,31 @@ test('correctly detects array and object modifications', async t => {
     data = await loadCacheJSON(t.context.path)
     t.deepEqual(data, {obj})
 })
+
+test('no conflicts with inherited object properties', async t => {
+    const path = t.context.path
+    let cache = await persistent(path, {dict: true}) // no cache yet, empty object created
+    cache.hi = 'hi'
+    cache.a = [1,2,3];
+    reservedKeys1.forEach(rk => t.assert(cache[rk] === undefined));
+    reservedKeys2.forEach(rk => t.assert(cache[rk] === undefined));
+    await persistent.close(cache)
+    cache = await persistent(path, {dict: true}) // there is a cache already, empty object loaded from JSON
+    t.assert(cache.hi === 'hi')
+    t.assert(Array.isArray(cache.a));
+    reservedKeys1.forEach(rk => t.assert(cache[rk] === undefined));
+    reservedKeys2.forEach(rk => t.assert(cache[rk] === undefined));
+
+    reservedKeys1.forEach(rk => {
+        cache[rk] = 'hello';
+        t.assert(cache[rk] === 'hello')
+    });
+    reservedKeys2.forEach(rk => {
+        cache[rk] = 'hello';
+        t.assert(cache[rk] === 'hello')
+    });
+    await persistent.close(cache)
+    cache = await persistent(path, {dict: true})
+    reservedKeys1.forEach(rk => t.assert(cache[rk] === 'hello'));
+    reservedKeys2.forEach(rk => t.assert(cache[rk] === 'hello'));
+})