how to use the sortedlastindexby function from lodash in javascript

The sortedLastIndexBy function from Lodash in JavaScript can be used to determine the index at which a given element should be inserted into a sorted array by iterating from right to left using a comparator function.

Here is an example of using sortedLastIndexBy function:

index.tsx
const _ = require('lodash');

const items = [
  { name: 'Tom', age: 23 },
  { name: 'Mary', age: 42 },
  { name: 'John', age: 18 }
];

// Declare the comparator function
const ageComparator = item => item.age;

// Use the sortedLastIndexBy function to get the index
const index = _.sortedLastIndexBy(items, { age: 25 }, ageComparator);

console.log(index);
// Output: 1 (the element should be inserted at index 1 to ensure the array remains sorted by age)
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In the example above, the sortedLastIndexBy function is used to determine the correct index where an object with an "age" property of 25 should be inserted into the "items" array by checking the "age" property of each object in the array using the ageComparator function. The result is the index "1", indicating that the new element should be inserted at index 1 to ensure the array remains sorted by age.

Note that the sortedLastIndexBy function assumes that the input array is already sorted. If it is not sorted, the function will produce incorrect results.