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Lodash _.flatten() 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 Lodash.flatten() method is used to flatten the array to one level deep.

Syntax:

flatten( array )

Parameter: This method accepts single parameter array that holds simple array or array of arrays.

Return Value: The return type of this function is array.

Note: Please install lodash module by using command npm install lodash before using the code given below.

Example 1: When 2D array of Integers is given.

Javascript




// Requiring the lodash library
const _ = require("lodash");
  
// Original array
let array1 = [[1, 2], [4, 5], [7, 8]]
  
// Using _.flatten() method
let newArray = _.flatten(array1);
  
// Printing original Array
console.log("original Array1: ", array1)
  
// Printing the newArray
console.log("new Array: ", newArray)


Output:

Example 2: When array of arrays of object is given.

Javascript




// Requiring the lodash library
const _ = require("lodash");
  
// Original array
let array1 = [[{ "a": 1 }], 
    [{ "b": 2 }, { "c": 3 }]]
  
// using _.flatten() method
let newArray = _.flatten(array1);
  
// printing original Array
console.log("original Array1: ", array1)
  
// printing the newArray
console.log("new Array: ", newArray)


Output: 

Example 3: When empty array of arrays is given.

Javascript




// Requiring the lodash library
const _ = require("lodash");
  
// Original array
let array1 = [[], [[[]]], [[]], []]
  
// Using _.flatten() method
let newArray = lodash.flatten(array1);
  
// Printing original Array
console.log("original Array1: ", array1)
  
// Printing the newArray
console.log("new Array: ", newArray)


Output:

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