how to use the findlastindex function from the underscore library in javascript

The findLastIndex function from the underscore library is used to find the index of the last element in an array that satisfies a particular condition.

Here's an example of how to use findLastIndex:

index.tsx
// Load the underscore library
var _ = require('underscore');

// Sample array of objects
var data = [
  {name: 'apple', price: 0.50},
  {name: 'banana', price: 0.25},
  {name: 'orange', price: 0.75},
  {name: 'pear', price: 0.60}
];

// Find the index of the last object with price less than or equal to 0.50
var index = _.findLastIndex(data, function(obj) {
  return obj.price <= 0.50;
});

console.log(index); // Output: 1
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In this example, we first load the underscore library. We then define an array of objects called data. We use the findLastIndex function from the underscore library to find the index of the last object in the data array whose price is less than or equal to $0.50.

The findLastIndex function takes two arguments: the first argument is the array we want to search, and the second argument is a callback function that defines the search condition. In this example, the callback function takes an object from the array as an argument and returns true if the object's price is less than or equal to $0.50.

The findLastIndex function returns the index of the last object in the array that satisfies the search condition.

Note that the findLastIndex function searches the array from right to left, starting with the last element in the array.