Jsonata Date to milliseconds convertion

https://try.jsonata.org/r0q7GnSOh

lstData.strValue.$toMillis($, '[Y]-[M]-[D]')

{

"lstData": [

{

"strFieldName":"ActivityDate",

"strValue": "2020-06-28",

"dateTimeStamp": 1594857600000

},

{

"strFieldName":"ActivityDate",

"strValue": "2020-07-10",

"dateTimeStamp": 1595116800000

},

{

"strFieldName":"ActivityDate",

"strValue": "2020-07-25",

"dateTimeStamp": 1595289600000

}

]

}