remove property from nested json array

I have an array like this:

[{
    "name": "1392",
    "data": [{
        "saat2": 46.5,
        "maah2": "01",
        "saal2": 1392
    }, {
        "saat2": 114.06,
        "maah2": "02",
        "saal2": 1392
    }, {
        "saat2": 134.03,
        "maah2": "03",
        "saal2": 1392
    }, {
        "saat2": 137.18,
        "maah2": "04",
        "saal2": 1392
    }, {
        "saat2": 170.34,
        "maah2": "05",
        "saal2": 1392
    }, {
        "saat2": 179.91,
        "maah2": "06",
        "saal2": 1392
    }, {
        "saat2": 192.8,
        "maah2": "07",
        "saal2": 1392
    }, {
        "saat2": 189.11,
        "maah2": "08",
        "saal2": 1392
    }, {
        "saat2": 191.91,
        "maah2": "09",
        "saal2": 1392
    }, {
        "saat2": 225.07,
        "maah2": "10",
        "saal2": 1392
    }, {
        "saat2": 200.7,
        "maah2": "11",
        "saal2": 1392
    }, {
        "saat2": 209.34,
        "maah2": "12",
        "saal2": 1392
    }]
}, {
    "name": "1393",
    "data": [{
        "saat2": 130.97,
        "maah2": "۰۱",
        "saal2": 1393
    }, {
        "saat2": 185.17,
        "maah2": "۰۲",
        "saal2": 1393
    }, {
        "saat2": 92.74,
        "maah2": "۰۳",
        "saal2": 1393
    }, {
        "saat2": 112.7,
        "maah2": "۰۴",
        "saal2": 1393
    }, {
        "saat2": 96.5,
        "maah2": "۰۵",
        "saal2": 1393
    }, {
        "saat2": 91.14,
        "maah2": "۰۶",
        "saal2": 1393
    }, {
        "saat2": 65.67,
        "maah2": "۰۷",
        "saal2": 1393
    }, {
        "saat2": 71.23,
        "maah2": "۰۸",
        "saal2": 1393
    }, {
        "saat2": 104.71,
        "maah2": "۰۹",
        "saal2": 1393
    }, {
        "saat2": 105.18,
        "maah2": "۱۰",
        "saal2": 1393
    }, {
        "saat2": 93.24,
        "maah2": "۱۱",
        "saal2": 1393
    }, {
        "saat2": 98.95,
        "maah2": "۱۲",
        "saal2": 1393
    }]
}, {
    "name": "1394",
    "data": [{
        "saat2": 86.15,
        "maah2": "۰۱",
        "saal2": 1394
    }, {
        "saat2": 47.4,
        "maah2": "۰۲",
        "saal2": 1394
    }, {
        "saat2": 41.07,
        "maah2": "۰۳",
        "saal2": 1394
    }, {
        "saat2": 51.99,
        "maah2": "۰۴",
        "saal2": 1394
    }, {
        "saat2": 71.92,
        "maah2": "۰۵",
        "saal2": 1394
    }, {
        "saat2": 682.53,
        "maah2": "۰۶",
        "saal2": 1394
    }, {
        "saat2": 50.29,
        "maah2": "۰۷",
        "saal2": 1394
    }, {
        "saat2": 87.66,
        "maah2": "۰۸",
        "saal2": 1394
    }, {
        "saat2": 49.19,
        "maah2": "۰۹",
        "saal2": 1394
    }, {
        "saat2": 60.7,
        "maah2": "۱۰",
        "saal2": 1394
    }, {
        "saat2": 69.21,
        "maah2": "۱۱",
        "saal2": 1394
    }, {
        "saat2": 54.23,
        "maah2": "۱۲",
        "saal2": 1394
    }]
}, {
    "name": "1395",
    "data": [{
        "saat2": 42.86,
        "maah2": "01",
        "saal2": 1395
    }, {
        "saat2": 99.04,
        "maah2": "02",
        "saal2": 1395
    }, {
        "saat2": 51.4,
        "maah2": "۰۳",
        "saal2": 1395
    }, {
        "saat2": 29.83,
        "maah2": "۰۴",
        "saal2": 1395
    }, {
        "saat2": 68.83,
        "maah2": "۰۵",
        "saal2": 1395
    }, {
        "saat2": 68.18,
        "maah2": "۰۶",
        "saal2": 1395
    }, {
        "saat2": 65.34,
        "maah2": "۰۷",
        "saal2": 1395
    }, {
        "saat2": 61.82,
        "maah2": "۰۸",
        "saal2": 1395
    }, {
        "saat2": 82.15,
        "maah2": "۰۹",
        "saal2": 1395
    }, {
        "saat2": 129.64,
        "maah2": "۱۰",
        "saal2": 1395
    }, {
        "saat2": 116.69,
        "maah2": "۱۱",
        "saal2": 1395
    }, {
        "saat2": 117.1,
        "maah2": "۱۲",
        "saal2": 1395
    }]
}, {
    "name": "1396",
    "data": [{
        "saat2": 70.22,
        "maah2": "۰۱",
        "saal2": 1396
    }, {
        "saat2": 109.9,
        "maah2": "۰۲",
        "saal2": 1396
    }, {
        "saat2": 82.15,
        "maah2": "۰۳",
        "saal2": 1396
    }, {
        "saat2": 55.22,
        "maah2": "۰۴",
        "saal2": 1396
    }, {
        "saat2": 108.07,
        "maah2": "۰۵",
        "saal2": 1396
    }, {
        "saat2": 98.84,
        "maah2": "۰۶",
        "saal2": 1396
    }, {
        "saat2": 104.56,
        "maah2": "۰۷",
        "saal2": 1396
    }, {
        "saat2": 84.16,
        "maah2": "۰۸",
        "saal2": 1396
    }, {
        "saat2": 71.8,
        "maah2": "۰۹",
        "saal2": 1396
    }, {
        "saat2": 123.09,
        "maah2": "۱۰",
        "saal2": 1396
    }, {
        "saat2": 110.8,
        "maah2": "۱۱",
        "saal2": 1396
    }, {
        "saat2": 162.28,
        "maah2": "۱۲",
        "saal2": 1396
    }]
}, {
    "name": "1397",
    "data": [{
        "saat2": 59.22,
        "maah2": "01",
        "saal2": 1397
    }, {
        "saat2": 63.7,
        "maah2": "02",
        "saal2": 1397
    }, {
        "saat2": 70.21,
        "maah2": "03",
        "saal2": 1397
    }, {
        "saat2": 103.82,
        "maah2": "04",
        "saal2": 1397
    }, {
        "saat2": 113.22,
        "maah2": "05",
        "saal2": 1397
    }, {
        "saat2": 108.05,
        "maah2": "06",
        "saal2": 1397
    }, {
        "saat2": 114.69,
        "maah2": "07",
        "saal2": 1397
    }, {
        "saat2": 56.49,
        "maah2": "08",
        "saal2": 1397
    }, {
        "saat2": 97.72,
        "maah2": "09",
        "saal2": 1397
    }, {
        "saat2": 54.23,
        "maah2": "10",
        "saal2": 1397
    }, {
        "saat2": 22.18,
        "maah2": "11",
        "saal2": 1397
    }, {
        "saat2": 58.61,
        "maah2": "12",
        "saal2": 1397
    }]
}, {
    "name": "1398",
    "data": [{
        "saat2": 15.45,
        "maah2": "01",
        "saal2": 1398
    }, {
        "saat2": 38.06,
        "maah2": "02",
        "saal2": 1398
    }, {
        "saat2": 27.07,
        "maah2": "03",
        "saal2": 1398
    }, {
        "saat2": 0.33,
        "maah2": "10",
        "saal2": 1398
    }, {
        "saat2": 6.78,
        "maah2": "11",
        "saal2": 1398
    }, {
        "saat2": 8.78,
        "maah2": "12",
        "saal2": 1398
    }]
}, {
    "name": "1399",
    "data": [{
        "saat2": 63.08,
        "maah2": "02",
        "saal2": 1399
    }, {
        "saat2": 29.82,
        "maah2": "03",
        "saal2": 1399
    }, {
        "saat2": 61.58,
        "maah2": "04",
        "saal2": 1399
    }, {
        "saat2": 36.59,
        "maah2": "05",
        "saal2": 1399
    }, {
        "saat2": 33.02,
        "maah2": "06",
        "saal2": 1399
    }, {
        "saat2": 58.86,
        "maah2": "07",
        "saal2": 1399
    }, {
        "saat2": 59.72,
        "maah2": "08",
        "saal2": 1399
    }, {
        "saat2": 33.99,
        "maah2": "09",
        "saal2": 1399
    }, {
        "saat2": 59.6,
        "maah2": "10",
        "saal2": 1399
    }, {
        "saat2": 70.01,
        "maah2": "11",
        "saal2": 1399
    }, {
        "saat2": 81.66,
        "maah2": "12",
        "saal2": 1399
    }]
}, {
    "name": "1400",
    "data": [{
        "saat2": 132.16,
        "maah2": "01",
        "saal2": 1400
    }, {
        "saat2": 61.96,
        "maah2": "02",
        "saal2": 1400
    }, {
        "saat2": 71.14,
        "maah2": "03",
        "saal2": 1400
    }, {
        "saat2": 54.3,
        "maah2": "04",
        "saal2": 1400
    }, {
        "saat2": 52.79,
        "maah2": "05",
        "saal2": 1400
    }, {
        "saat2": 37.68,
        "maah2": "06",
        "saal2": 1400
    }]
}]

I want to remove saal2 and it’s value.I tried map and reduce but got no success.

Answer

you can do it like this, iterating over the starting array and deleting the nested property for each data object

start.forEach(se => se.data.forEach(a => delete a.saal2))

const start = [{
  "name": "1392",
  "data": [{
    "saat2": 46.5,
    "maah2": "01",
    "saal2": 1392
  }, {
    "saat2": 114.06,
    "maah2": "02",
    "saal2": 1392
  }, {
    "saat2": 134.03,
    "maah2": "03",
    "saal2": 1392
  }, {
    "saat2": 137.18,
    "maah2": "04",
    "saal2": 1392
  }, {
    "saat2": 170.34,
    "maah2": "05",
    "saal2": 1392
  }, {
    "saat2": 179.91,
    "maah2": "06",
    "saal2": 1392
  }, {
    "saat2": 192.8,
    "maah2": "07",
    "saal2": 1392
  }, {
    "saat2": 189.11,
    "maah2": "08",
    "saal2": 1392
  }, {
    "saat2": 191.91,
    "maah2": "09",
    "saal2": 1392
  }, {
    "saat2": 225.07,
    "maah2": "10",
    "saal2": 1392
  }, {
    "saat2": 200.7,
    "maah2": "11",
    "saal2": 1392
  }, {
    "saat2": 209.34,
    "maah2": "12",
    "saal2": 1392
  }]
}, {
  "name": "1393",
  "data": [{
    "saat2": 130.97,
    "maah2": "۰۱",
    "saal2": 1393
  }, {
    "saat2": 185.17,
    "maah2": "۰۲",
    "saal2": 1393
  }, {
    "saat2": 92.74,
    "maah2": "۰۳",
    "saal2": 1393
  }, {
    "saat2": 112.7,
    "maah2": "۰۴",
    "saal2": 1393
  }, {
    "saat2": 96.5,
    "maah2": "۰۵",
    "saal2": 1393
  }, {
    "saat2": 91.14,
    "maah2": "۰۶",
    "saal2": 1393
  }, {
    "saat2": 65.67,
    "maah2": "۰۷",
    "saal2": 1393
  }, {
    "saat2": 71.23,
    "maah2": "۰۸",
    "saal2": 1393
  }, {
    "saat2": 104.71,
    "maah2": "۰۹",
    "saal2": 1393
  }, {
    "saat2": 105.18,
    "maah2": "۱۰",
    "saal2": 1393
  }, {
    "saat2": 93.24,
    "maah2": "۱۱",
    "saal2": 1393
  }, {
    "saat2": 98.95,
    "maah2": "۱۲",
    "saal2": 1393
  }]
}, {
  "name": "1394",
  "data": [{
    "saat2": 86.15,
    "maah2": "۰۱",
    "saal2": 1394
  }, {
    "saat2": 47.4,
    "maah2": "۰۲",
    "saal2": 1394
  }, {
    "saat2": 41.07,
    "maah2": "۰۳",
    "saal2": 1394
  }, {
    "saat2": 51.99,
    "maah2": "۰۴",
    "saal2": 1394
  }, {
    "saat2": 71.92,
    "maah2": "۰۵",
    "saal2": 1394
  }, {
    "saat2": 682.53,
    "maah2": "۰۶",
    "saal2": 1394
  }, {
    "saat2": 50.29,
    "maah2": "۰۷",
    "saal2": 1394
  }, {
    "saat2": 87.66,
    "maah2": "۰۸",
    "saal2": 1394
  }, {
    "saat2": 49.19,
    "maah2": "۰۹",
    "saal2": 1394
  }, {
    "saat2": 60.7,
    "maah2": "۱۰",
    "saal2": 1394
  }, {
    "saat2": 69.21,
    "maah2": "۱۱",
    "saal2": 1394
  }, {
    "saat2": 54.23,
    "maah2": "۱۲",
    "saal2": 1394
  }]
}, {
  "name": "1395",
  "data": [{
    "saat2": 42.86,
    "maah2": "01",
    "saal2": 1395
  }, {
    "saat2": 99.04,
    "maah2": "02",
    "saal2": 1395
  }, {
    "saat2": 51.4,
    "maah2": "۰۳",
    "saal2": 1395
  }, {
    "saat2": 29.83,
    "maah2": "۰۴",
    "saal2": 1395
  }, {
    "saat2": 68.83,
    "maah2": "۰۵",
    "saal2": 1395
  }, {
    "saat2": 68.18,
    "maah2": "۰۶",
    "saal2": 1395
  }, {
    "saat2": 65.34,
    "maah2": "۰۷",
    "saal2": 1395
  }, {
    "saat2": 61.82,
    "maah2": "۰۸",
    "saal2": 1395
  }, {
    "saat2": 82.15,
    "maah2": "۰۹",
    "saal2": 1395
  }, {
    "saat2": 129.64,
    "maah2": "۱۰",
    "saal2": 1395
  }, {
    "saat2": 116.69,
    "maah2": "۱۱",
    "saal2": 1395
  }, {
    "saat2": 117.1,
    "maah2": "۱۲",
    "saal2": 1395
  }]
}, {
  "name": "1396",
  "data": [{
    "saat2": 70.22,
    "maah2": "۰۱",
    "saal2": 1396
  }, {
    "saat2": 109.9,
    "maah2": "۰۲",
    "saal2": 1396
  }, {
    "saat2": 82.15,
    "maah2": "۰۳",
    "saal2": 1396
  }, {
    "saat2": 55.22,
    "maah2": "۰۴",
    "saal2": 1396
  }, {
    "saat2": 108.07,
    "maah2": "۰۵",
    "saal2": 1396
  }, {
    "saat2": 98.84,
    "maah2": "۰۶",
    "saal2": 1396
  }, {
    "saat2": 104.56,
    "maah2": "۰۷",
    "saal2": 1396
  }, {
    "saat2": 84.16,
    "maah2": "۰۸",
    "saal2": 1396
  }, {
    "saat2": 71.8,
    "maah2": "۰۹",
    "saal2": 1396
  }, {
    "saat2": 123.09,
    "maah2": "۱۰",
    "saal2": 1396
  }, {
    "saat2": 110.8,
    "maah2": "۱۱",
    "saal2": 1396
  }, {
    "saat2": 162.28,
    "maah2": "۱۲",
    "saal2": 1396
  }]
}, {
  "name": "1397",
  "data": [{
    "saat2": 59.22,
    "maah2": "01",
    "saal2": 1397
  }, {
    "saat2": 63.7,
    "maah2": "02",
    "saal2": 1397
  }, {
    "saat2": 70.21,
    "maah2": "03",
    "saal2": 1397
  }, {
    "saat2": 103.82,
    "maah2": "04",
    "saal2": 1397
  }, {
    "saat2": 113.22,
    "maah2": "05",
    "saal2": 1397
  }, {
    "saat2": 108.05,
    "maah2": "06",
    "saal2": 1397
  }, {
    "saat2": 114.69,
    "maah2": "07",
    "saal2": 1397
  }, {
    "saat2": 56.49,
    "maah2": "08",
    "saal2": 1397
  }, {
    "saat2": 97.72,
    "maah2": "09",
    "saal2": 1397
  }, {
    "saat2": 54.23,
    "maah2": "10",
    "saal2": 1397
  }, {
    "saat2": 22.18,
    "maah2": "11",
    "saal2": 1397
  }, {
    "saat2": 58.61,
    "maah2": "12",
    "saal2": 1397
  }]
}, {
  "name": "1398",
  "data": [{
    "saat2": 15.45,
    "maah2": "01",
    "saal2": 1398
  }, {
    "saat2": 38.06,
    "maah2": "02",
    "saal2": 1398
  }, {
    "saat2": 27.07,
    "maah2": "03",
    "saal2": 1398
  }, {
    "saat2": 0.33,
    "maah2": "10",
    "saal2": 1398
  }, {
    "saat2": 6.78,
    "maah2": "11",
    "saal2": 1398
  }, {
    "saat2": 8.78,
    "maah2": "12",
    "saal2": 1398
  }]
}, {
  "name": "1399",
  "data": [{
    "saat2": 63.08,
    "maah2": "02",
    "saal2": 1399
  }, {
    "saat2": 29.82,
    "maah2": "03",
    "saal2": 1399
  }, {
    "saat2": 61.58,
    "maah2": "04",
    "saal2": 1399
  }, {
    "saat2": 36.59,
    "maah2": "05",
    "saal2": 1399
  }, {
    "saat2": 33.02,
    "maah2": "06",
    "saal2": 1399
  }, {
    "saat2": 58.86,
    "maah2": "07",
    "saal2": 1399
  }, {
    "saat2": 59.72,
    "maah2": "08",
    "saal2": 1399
  }, {
    "saat2": 33.99,
    "maah2": "09",
    "saal2": 1399
  }, {
    "saat2": 59.6,
    "maah2": "10",
    "saal2": 1399
  }, {
    "saat2": 70.01,
    "maah2": "11",
    "saal2": 1399
  }, {
    "saat2": 81.66,
    "maah2": "12",
    "saal2": 1399
  }]
}, {
  "name": "1400",
  "data": [{
    "saat2": 132.16,
    "maah2": "01",
    "saal2": 1400
  }, {
    "saat2": 61.96,
    "maah2": "02",
    "saal2": 1400
  }, {
    "saat2": 71.14,
    "maah2": "03",
    "saal2": 1400
  }, {
    "saat2": 54.3,
    "maah2": "04",
    "saal2": 1400
  }, {
    "saat2": 52.79,
    "maah2": "05",
    "saal2": 1400
  }, {
    "saat2": 37.68,
    "maah2": "06",
    "saal2": 1400
  }]
}];

start.forEach(se => se.data.forEach(a => delete a.saal2))

console.log(start)