how to update subarray elements in javascript

Question

I am trying to update nested array elements in javascript. want to convert dates into different format. how i can updates nested elements

array1 = [
{
"week": [
"2019-05-06T16:00:00.000Z",
"2019-05-07T16:00:00.000Z",
"2019-05-08T16:00:00.000Z",
"2019-05-09T16:00:00.000Z",
"2019-05-10T16:00:00.000Z",
"2019-05-11T16:00:00.000Z",
"2019-05-12T16:00:00.000Z"
],
"weekNumber": 19
},
{
"week": [
"2019-05-20T16:00:00.000Z",
"2019-05-21T16:00:00.000Z",
"2019-05-22T16:00:00.000Z",
"2019-05-23T16:00:00.000Z",
"2019-05-24T16:00:00.000Z",
"2019-05-25T16:00:00.000Z",
"2019-05-26T16:00:00.000Z"
],
"weekNumber": 21
},
{
"week": [
"2019-06-03T16:00:00.000Z",
"2019-06-04T16:00:00.000Z",
"2019-06-05T16:00:00.000Z",
"2019-06-06T16:00:00.000Z",
"2019-06-07T16:00:00.000Z",
"2019-06-08T16:00:00.000Z",
"2019-06-09T16:00:00.000Z"
],
"weekNumber": 23
}
];
expectedResult = [
{
"week": [
"2019-05-06",
"2019-05-07",
"2019-05-08",
"2019-05-09",
"2019-05-10",
"2019-05-11",
"2019-05-12"
],
"weekNumber": 19
},
{
"week": [
"2019-05-20",
"2019-05-21",
"2019-05-22",
"2019-05-23",
"2019-05-24",
"2019-05-25",
"2019-05-26"
],
"weekNumber": 21
},
{
"week": [
"2019-06-03",
"2019-06-04",
"2019-06-05",
"2019-06-06",
"2019-06-07",
"2019-06-08",
"2019-06-09"
],
"weekNumber": 23
}
];

want to remove ":00:00.000Z" . I have format function which removed that but do not know how to call here

want to remove ":00:00.000Z" . I have format function which removed that but do not know how to call here

Answer 1

You can use map and split

let array1 = [{"week": ["2019-05-06T16:00:00.000Z","2019-05-07T16:00:00.000Z","2019-05-08T16:00:00.000Z","2019-05-09T16:00:00.000Z","2019-05-10T16:00:00.000Z","2019-05-11T16:00:00.000Z","2019-05-12T16:00:00.000Z"],"weekNumber": 19},
{"week": ["2019-05-20T16:00:00.000Z","2019-05-21T16:00:00.000Z","2019-05-22T16:00:00.000Z","2019-05-23T16:00:00.000Z","2019-05-24T16:00:00.000Z","2019-05-25T16:00:00.000Z","2019-05-26T16:00:00.000Z"],"weekNumber": 21},
{"week": ["2019-06-03T16:00:00.000Z","2019-06-04T16:00:00.000Z","2019-06-05T16:00:00.000Z","2019-06-06T16:00:00.000Z","2019-06-07T16:00:00.000Z","2019-06-08T16:00:00.000Z","2019-06-09T16:00:00.000Z"],"weekNumber": 23}];
let op = array1.map(e=>{
 e.week = e.week.map(val => val.split('T',1)[0])
 return e
})
console.log(op)

Answer 2

You can use map if you want a new array of can use map inside a forEach. Basically you need to use nested map.

This example shows use of two map, one nested inside another. In the nested map , the week is iterated and here the Date object is use. If you have a separate function you can call it inside nested map call back function like this

 let newfmt = array1.map(function(item) {
 return {
 week: item.week.map(function(elem) {
 // here elem will be each value inside the week array.
 // since map create an array here week will be an array of formatted dates
 return yourFunction(elem)
 }),
 weekNumber: item.weekNumber
 }
 })

let array1 = [{
 "week": [
 "2019-05-06T16:00:00.000Z",
 "2019-05-07T16:00:00.000Z",
 "2019-05-08T16:00:00.000Z",
 "2019-05-09T16:00:00.000Z",
 "2019-05-10T16:00:00.000Z",
 "2019-05-11T16:00:00.000Z",
 "2019-05-12T16:00:00.000Z"
 ],
 "weekNumber": 19
 },
 {
 "week": [
 "2019-05-20T16:00:00.000Z",
 "2019-05-21T16:00:00.000Z",
 "2019-05-22T16:00:00.000Z",
 "2019-05-23T16:00:00.000Z",
 "2019-05-24T16:00:00.000Z",
 "2019-05-25T16:00:00.000Z",
 "2019-05-26T16:00:00.000Z"
 ],
 "weekNumber": 21
 },
 {
 "week": [
 "2019-06-03T16:00:00.000Z",
 "2019-06-04T16:00:00.000Z",
 "2019-06-05T16:00:00.000Z",
 "2019-06-06T16:00:00.000Z",
 "2019-06-07T16:00:00.000Z",
 "2019-06-08T16:00:00.000Z",
 "2019-06-09T16:00:00.000Z"
 ],
 "weekNumber": 23
 }
];
let newfmt = array1.map(function(item) {
 return {
 week: item.week.map(function(elem) {
 let dt = new Date(elem);
 return `${dt.getFullYear()}-${dt.getMonth()}-${dt.getDay()}`
 }),
 weekNumber: item.weekNumber
 }
})
 console.log(newfmt)

Answer 3

You can use Object.assign for example:-

const a = { x: "Hi", y: "Test" } const b = Object.assign({}, a, { x: "Bye" }); console.log(b);

Here rather then x: "Bye" you can iterate on week and do the formatting.

• Gourishankar: Yes, using map is a much better way.