Get multiple list items by ID in SharePoint List - sharepoint-2013

Question

I am trying to retrieve a list items from a SharePoint list but my issue is that I would like to retrieve the last four items by ID and I don't know how to proceed using JSOM.
Can someone help me whit some CAML code on how to do that?
var ctx = new SP.ClientContext.get_current();
var web = ctx.get_web();
//Geting reference to the list
var olist = web.get_lists().getByTitle('Configs');
var oitem = olist.getItemById(1);
//get Title,id,ConfigItem fields
ctx.load(oitem, "Title", "Id", "ConfigItem");
ctx.executeQueryAsync(function () {
alert(oitem.get_item("Title"));
alert(oitem.get_item("ConfigItem"));
}, function (a, b) {
alert(b.get_message());
});

Answer 1

You could use rest api with order by and $top option for this requirement.
/_api/web/lists/getbytitle('chart')/items?$select=ID,Title&$orderby= ID desc&$top=4
Rest api get list items.
$.ajax({
url: _spPageContextInfo.webAbsoluteUrl + "/_api/web/lists/getbytitle('chart')/items?$select=ID,Title&$orderby= ID desc&$top=4",
type: "GET",
headers:
{
"Accept": "application/json;odata=verbose",
"Content-Type": "application/json;odata=verbose"
},
success: function (data) {
for (var i = 0; i < data.d.results.length; i++) {
var item = data.d.results[i];
//to do
}
},
error: function (data) {
console.log(data.responseJSON.error);
}
});

Answer 2

Here is JSOM solution with use of CamlQuery.
var ctx = new SP.ClientContext.get_current();
var web = ctx.get_web();
var query = new SP.CamlQuery()
query.set_viewXml("<View><Query><OrderBy><FieldRef Name='ID' Ascending='FALSE' /></OrderBy></Query><RowLimit>4</RowLimit></View>")
var list = web.get_lists().getByTitle('Configs');
var items = list.getItems(query, "ID", "Title", "FirstName", "LastName", "Level", "Grade", "Date");
var dictionary = [];
ctx.load(items);
ctx.executeQueryAsync(function () {
var enumerator = items.getEnumerator();
while (enumerator.moveNext()) {
var item = enumerator.get_current();
dictionary.push({
title: item.get_item("Title"),
firstName: item.get_item("FirstName"),
lastName: item.get_item("LastName"),
level: item.get_item("Level"),
grade: item.get_item("Grade"),
date: item.get_item("Date"),
});
}
}, function (a, b) {
alert(b.get_message());
});