数组中对象去重

let coupons=[ { "id": 95, "appId": "mitang", "deleted": false, "creator": null, "created": 1520560522000, "modifier": null, "modified": 1520560522000, "pageSize": null, "offset": null, "type": 1, "typeId": 76, "userId": 108, "guideId": 32216, "storeId": null, "couponId": 3, "couponSn": "mt0000000001", "startTime": 1520560522000, "endTime": 1520560522000, "couponName": "发生的发生", "remark": "", "couponPackId": null, "writeOff": 0, "face": "10" }, { "id": 95, "appId": "mitang", "deleted": false, "creator": null, "created": 1520560522000, "modifier": null, "modified": 1520560522000, "pageSize": null, "offset": null, "type": 1, "typeId": 76, "userId": 108, "guideId": 32216, "storeId": null, "couponId": 3, "couponSn": "mt0000000001", "startTime": 1520560522000, "endTime": 1520560522000, "couponName": "发生的发生", "remark": "", "couponPackId": null, "writeOff": 0, "face": "10" } ]

 {};
coupons.forEach(function (gpa) {
unique[JSON.stringify(gpa)] = gpa
});
coupons = Object.keys(unique).map(function (u) {
return JSON.parse(u)
});