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Table of contents
1.
Introduction
2.
Why This Function is Used
3.
Syntax, Parameter and Return Value
3.1.
Syntax:
3.2.
Parameters:
3.3.
Return Value: 
4.
Examples 
4.1.
Invoking a Method on Array Elements:
4.2.
JavaScript
4.3.
Applying a Method to Objects in an Array:
4.4.
JavaScript
4.5.
Using a Custom Function:
4.6.
JavaScript
4.7.
Invoking with Additional Arguments:
4.8.
JavaScript
5.
Frequently Asked Questions 
5.1.
How does _.invokeMap() handle elements that don't have the specified method?
5.2.
Can _.invokeMap() be used with a method that modifies the original elements?
5.3.
Is _.invokeMap() efficient for large collections?
6.
Conclusion
Last Updated: Mar 27, 2024
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Lodash _.invokeMap() Method

Author Riya Singh
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Introduction

Manipulating collections by invoking a method on each element can streamline complex operations in JavaScript. This is where Lodash's _.invokeMap() comes into play. It applies a specified method to each element in a collection, which can be especially useful when dealing with arrays of objects or nested structures. 

Lodash _.invokeMap() Method

This article will explore the _.invokeMap() method, highlighting its functionality, syntax, and practical applications through examples and FAQs.

Why This Function is Used

The _.invokeMap() function is used for invoking a specified method on each element in a collection. It's particularly useful in scenarios where a uniform operation needs to be performed on all elements, such as transforming data, applying a function, or extracting information. This method simplifies the process of applying consistent transformations across a collection, enhancing code efficiency and readability.

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Syntax, Parameter and Return Value

Syntax:

 _.invokeMap(collection, path, [args])

Parameters:

  • collection (Array|Object): The collection to iterate over.
     
  • path (Array|string): The path of the method to invoke or the function to invoke.
     
  • [args] (...*): The arguments to invoke the method with.

Return Value: 

(Array) - Returns the result of invoking the method on each element.

Examples 

Invoking a Method on Array Elements:

  • JavaScript

JavaScript

var _ = require('lodash');

var strings = ['123', '456', '789'];

var parsedIntegers = _.invokeMap(strings, parseInt);

console.log(parsedIntegers);

 Output: 

[123, 456, 789]


Demonstrates invoking parseInt on each string in the array.

Applying a Method to Objects in an Array:

  • JavaScript

JavaScript

var objects = [{ 'value': '10' }, { 'value': '20' }, { 'value': '30' }];

var values = _.invokeMap(objects, 'value.toString');

console.log(values);

Output: 

['10', '20', '30']


Shows invoking the toString method on a property of each object.

Using a Custom Function:

  • JavaScript

JavaScript

var numbers = [1, 2, 3];

var doubled = _.invokeMap(numbers, num => num * 2);

console.log(doubled);

Output:

 [2, 4, 6]


An example of invoking a custom function to double each number.

Invoking with Additional Arguments:

  • JavaScript

JavaScript

var collections = [['a', 'b'], ['c', 'd']];

var joinedStrings = _.invokeMap(collections, 'join', '-');

console.log(joinedStrings);

 Output: 

['a-b', 'c-d']


Demonstrates invoking the join method with an additional argument.

Frequently Asked Questions 

How does _.invokeMap() handle elements that don't have the specified method?

If an element doesn’t have the specified method, _.invokeMap() will return undefined for that element.

Can _.invokeMap() be used with a method that modifies the original elements?

Yes, if the invoked method modifies the elements, those changes will reflect in the original collection.

Is _.invokeMap() efficient for large collections?

_.invokeMap() is generally efficient, but its performance depends on the complexity of the method being invoked and the size of the collection.

Conclusion

Lodash's _.invokeMap() method is a powerful and flexible tool for uniformly applying a method or function to each element in a collection. It simplifies complex data transformations and method invocations, making code more concise and readable.

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