Slice array and concat in javascript

Question

In case when arr = [1, 2, 3, 4] all works great.

var arr = [1, 2, 3, 4];

function range(min, max) {
    var startArr = arr.slice(arr.indexOf(min)),
        endArr = max < arr.length ? arr.slice(0, arr.indexOf(max) + 1) : [];
    return startArr.concat(endArr);
}


range(3,1);

But in case when arr = [{id:1, name: "John"}, {id:2, name: "Mark"}, {id:3, name: "Jim"},{id:4, name: "Bob"}] this code not works.

jsfiddle

Answer 1

Consider using the 'lodash' javascript library https://lodash.com/

For an 'array'

Sounds like you are after either

1. Slice - http://devdocs.io/lodash/index#slice
2. TakeWhile

Answer 2

This is because of the indexOf() part of your function is looking for the index based on the value. In your first array there are elements with the value 3 and 1 , but the second is an array of objects, so clearly it will not correct find them. Instead simply use the direct index given. Use the values of max,min as the index themselves. Note that the index goes from 0 .. n-1 rather than 1 .. n . So then range(3,1) would be range(2,0) ( if you want to use it as range(3,1) just subtract 1 from the values inside the function ):

function range(min, max) {
    var startArr = max >= min ? arr.slice(min, max + 1) : arr.slice(min),
        endArr = max < min ? arr.slice(0, max + 1) : [];
    return startArr.concat(endArr);
}
...
range(2, 0);

Fiddle Example