Javascript - Declaring an array a variable and slicing

Question

I have an array of objects that I'm attempting to slice at a different index depending on the URL.

data.Results.Data is my array.

I declared a variable arrList to equal data.Results.Data when console.logging my arrList I see the results I am expecting.

When starting my condition and slicing at different indexes and then console.logging the array I am getting back the entire array not the sliced array I am expecting.

Here is my code:

function retrieveData(data) {
  const arrList = data.Results.Data;
  const urlStr = window.location.pathname;
  if (urlStr.includes("/states/")) {
    arrList.slice(23, 46);
    console.log(arrList, "Slice");
  } else if (urlStr.includes("/countries/")) {
    arrList.slice(46, 69);
    console.log(arrList, "Slice");
  } else if (urlStr.includes("/cities/")) {
    arrList.slice(69, 90);
    console.log(arrList, "Slice");
  }
}

I've tried declaring arrList inside of the condition statement which works, but I would like the variable arrList available throughout the entire scope of the function. I am expecting to see the sliced array when the condition is met.

you can create a new variable and assign the original array to it then slice like that: arr = arr.slice(beginning,end); and to deep copy an object so you really keep the original intact you can do like that: arr = JSON.parse(JSON.stringify(arrList)) — Giggs
– Giggs, Commented Apr 29, 2020 at 14:19

xdeepakv · Accepted Answer · 2020-04-29 14:32:46Z

1

slice does not replace or modify the existing array.. You need to redefine it

arrList = arrList.slice(69, 90)

Else use splice.

function retrieveData(data) {
  const arrList = data.Results.Data;
  const urlStr = window.location.pathname;
  let slicedData = [];
  if (urlStr.includes("/states/")) {
    slicedData = arrList.slice(23, 46);
    console.log(arrList, "Slice");
  } else if (urlStr.includes("/countries/")) {
    slicedData = arrList.slice(46, 69);
    console.log(arrList, "Slice");
  } else if (urlStr.includes("/cities/")) {
    slicedData = arrList.slice(69, 90);
    console.log(arrList, "Slice");
  }
  return slicedData;
}

edited Apr 29, 2020 at 14:32

answered Apr 29, 2020 at 14:17

xdeepakv

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2 Comments

kurtixl Over a year ago

I'm sorry, I'm confused about the redinfe part. I am trying to access the sliced array outside of the condition. if I am re-defining arrList = arrList.slice am I leaving the arrList = data.Results.Data variable at the start of the function?

xdeepakv Over a year ago

yes u can do that. create a variable. I have update my answer check

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