Lodash _.sortedIndexBy() Method

Lodash _.sortedIndexBy() method is used to return the lowest index of the array where an element can be inserted and maintain its sorted order. In addition, it accepts iteratee which is invoked for value and each element of the array to compute their sort ranking. It uses the binary search.

Syntax:

_.sortedIndexBy(array, value, [iteratee=_.identity]);

Parameters:

• array: This parameter holds the sorted array.
• value: This parameter holds the value to evaluate.
• Iteratee: This is the function that iterates over each element.

Return Value:

• This method returns the index at which the value should be inserted into the array.

Example 1: In this example, we are getting the index at which we can insert the given value.

// Requiring the lodash library 
const _ = require("lodash");

// Original array 
let objects = [{ 'x': 4 }, { 'x': 6 }];

// Use of _.sortedIndexBy() 
// method 
let index = _.sortedIndexBy(objects,
    { 'x': 5 }, function (o) { return o.x; });

// Printing the output 
console.log(index); 

Output:

1

Example 2: In this example, we are getting the index at which we can insert the given value.

// Requiring the lodash library 
const _ = require("lodash");

// Original array 
let objects = [{ 'x': 4 }, { 'x': 6 }];

// Use of _.sortedIndexBy() 
// method 
let index = _.sortedIndexBy(objects, { 'x': 9 }, 'x');

// Printing the output 
console.log(index); 

Output:

2

Example 3: In this example, we are getting the index at which we can insert the given value.

// Requiring the lodash library 
const _ = require("lodash");

// Original array 
let x = ['ajax', 'django', 'mongoDb',
    'react', 'reactnative', 'yarn']

// Use of _.sortedIndexBy() 
// method 
let index = _.sortedIndexBy(x, 'luby', 5);

// Printing the output 
console.log(index); 

Output:

3

Note: This will not work in normal JavaScript because it requires the library lodash to be installed.