How to compare rows from JSON file in angular?

I have this items in a JSON file that I need to compare wherever I have Curr or Prev values and compare if they are equals. this algorithm is with angular 5 but I'm being unable to do this, I did the load function with httpClient Example :

[{
    "id": 1,
    "comparisonDate": "2017-06-22",
    "milestone": "CURR_PREV",
    "udDomain": "BASIS",
    "udIdentifier": "332A251000.01",
    "rpt": "D70",
    "approvedCurr": true,
    "approvedPrev": null,
    "commercialReferenceCurr": "BASIS - 01.01.2007",
    "commercialReferencePrev": null,
    "customizationImpactCurr": null,
    "customizationImpactPrev": null,
    "deliveryTypeCurr": null,
    "deliveryTypePrev": null,
    "aircraftId": 184,
    "aircraftSapId": "580652",
    "aircraftName": "BUL 011",
    "aircraftSerialNumber": "02713",
    "quantityCurr": "1",
    "quantityPrev": null,
    "statusCurr": "O",
    "statusPrev": null,
    "typeModification": "CREATION",
    "validityCurr": "V",
    "validityPrev": null
}, {
    "id": 2,
    "comparisonDate": "2017-06-22",
    "milestone": "CURR_PREV",
    "udDomain": "BASIS",
    "udIdentifier": "332A270028.01",
    "rpt": "E15",
    "approvedCurr": true,
    "approvedPrev": null,
    "commercialReferenceCurr": "BASIS - 01.01.2007",
    "commercialReferencePrev": null,
    "customizationImpactCurr": null,
    "customizationImpactPrev": null,
    "deliveryTypeCurr": null,
    "deliveryTypePrev": null,
    "aircraftId": 184,
    "aircraftSapId": "580652",
    "aircraftName": "BUL 011",
    "aircraftSerialNumber": "02713",
    "quantityCurr": "1",
    "quantityPrev": null,
    "statusCurr": "O",
    "statusPrev": null,
    "typeModification": "CREATION",
    "validityCurr": "V",
    "validityPrev": null
}]

this should be with using lodash.

Solution

i assume your want something like this

for each object in your array
filter keys that end with "Curr"
for each get Prev property

compare it with curr property

let obj = [{
"id": 1,
"comparisonDate": "2017-06-22",
"milestone": "CURR_PREV",
"udDomain": "BASIS",
"udIdentifier": "332A251000.01",
"rpt": "D70",
"approvedCurr": true,
"approvedPrev": null,
"commercialReferenceCurr": "BASIS - 01.01.2007",
"commercialReferencePrev": null,
"customizationImpactCurr": null,
"customizationImpactPrev": null,
"deliveryTypeCurr": null,
"deliveryTypePrev": null,
"aircraftId": 184,
"aircraftSapId": "580652",
"aircraftName": "BUL 011",
"aircraftSerialNumber": "02713",
"quantityCurr": "1",
"quantityPrev": null,
"statusCurr": "O",
"statusPrev": null,
"typeModification": "CREATION",
"validityCurr": "V",
"validityPrev": null
}, {
"id": 2,
"comparisonDate": "2017-06-22",
"milestone": "CURR_PREV",
"udDomain": "BASIS",
"udIdentifier": "332A270028.01",
"rpt": "E15",
"approvedCurr": true,
"approvedPrev": null,
"commercialReferenceCurr": "BASIS - 01.01.2007",
"commercialReferencePrev": null,
"customizationImpactCurr": null,
"customizationImpactPrev": null,
"deliveryTypeCurr": null,
"deliveryTypePrev": null,
"aircraftId": 184,
"aircraftSapId": "580652",
"aircraftName": "BUL 011",
"aircraftSerialNumber": "02713",
"quantityCurr": "1",
"quantityPrev": null,
"statusCurr": "O",
"statusPrev": null,
"typeModification": "CREATION",
"validityCurr": "V",
"validityPrev": null
 }];


obj.forEach(x=>{
  Object.keys(x)
   .filter(y=>y.endsWith("Curr"))
   .forEach(y=>{
     let prevProp = y.replace("Curr", "Prev")
     console.log(y, x[y]);
     console.log(prevProp ,x[prevProp ]);
     if(x[y]===x[prevProp ]){
       //equal
     }else{
       //not equal
     }
 })

})

you could use lodash's _.forEach, _.Keys, _.filter but i think there is not much point on this.