Lodash _.thru() Method

Lodash is a JavaScript library that works on the top of underscore.js. Lodash helps in working with arrays, strings, objects, numbers, etc.

The _.thru() method of Sequence in lodash is similar to _.tap() method and the only difference is that it returns the outcome of the interceptor. Moreover, this method is mainly used to “pass thru” values in a method chain sequence by replacing intermediate results.

Syntax:

_.thru(value, interceptor)

Parameters: This method accepts two parameters as mentioned above and described below:

• value: It is the value to be given to the interceptor.
• interceptor: It is the function to be called.

Return Value: This method returns the result of the interceptor.

Example 1:

Javascript

// Requiring lodash library
const _ = require('lodash');

// Calling thru() method
let result = _(144).thru(function(value) {
   return [value];
 }).value();

 // Displays output
 console.log(result);

Output:

[ 144 ]

Example 2:

Javascript

// Requiring lodash library
const _ = require('lodash');

// Calling thru() method
let result = _('GfG').thru(function(value) {
   return [value];
 }).value();

 // Displays output
 console.log(result);

Output:

[ 'GfG' ]

Example 3:

Javascript

// Requiring lodash library
const _ = require('lodash');

// Defining value
var val = ['g', 'f', 'G']

// Calling thru() method along with
// reverse and chain method
let result = _(val).reverse()
                   .chain()
                   .thru(function(value) {
    return [value];
 })
 .value();

 // Displays output
 console.log(result);

Output:

[ [ 'G', 'f', 'g' ] ]

Here, the output is reversed as reverse() method is used above in order to reverse the order of the value stated.

Reference: https://lodash.com/docs/4.17.15#thru