Tutorials

Lodash _.methodOf() Util Method

Posted in lodash Tutorial

Updated on Mar 15, 2024

By Mari Selvan

👁️ 18 - Views

⏳ 4 mins

💬 1 Comment

Photo Credit to CodeToFun

🙋 Introduction

In the landscape of JavaScript development, efficient manipulation of objects and functions is essential. Lodash, a comprehensive utility library, offers a plethora of functions to simplify common tasks. Among these functions is _.methodOf(), a versatile utility method that allows for dynamic invocation of object methods.

This method provides flexibility and convenience in handling object-oriented programming paradigms.

🧠 Understanding _.methodOf() Method

The _.methodOf() method in Lodash facilitates the dynamic invocation of methods belonging to an object. By specifying the object and method name as arguments, developers can execute functions within the context of the provided object. This enables streamlined access to object methods, enhancing code modularity and readability.

💡 Syntax

The syntax for the _.methodOf() method is straightforward:

syntax.js

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_.methodOf(object, methodName)

object: The object containing the method to invoke.
methodName: The name of the method to invoke.

📝 Example

Let's dive into a simple example to illustrate the usage of the _.methodOf() method:

example.js

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const _ = require('lodash');
const user = {
  name: 'John',
  greet() {
    return `Hello, ${this.name}!`;
  }
};
const greetingFunction = _.methodOf(user, 'greet');
const greeting = greetingFunction();
console.log(greeting);
// Output: Hello, John!

In this example, _.methodOf() is used to dynamically invoke the greet() method belonging to the user object, resulting in the expected greeting message.

🏆 Best Practices

When working with the _.methodOf() method, consider the following best practices:

Validate Input Objects:

Before using _.methodOf(), ensure that the input object contains the desired method. Performing validation checks can prevent runtime errors and enhance code robustness.

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const car = {
    brand: 'Toyota',
    startEngine() {
        console.log('Engine started.');
    }
};

if (_.has(car, 'startEngine')) {
    const startCar = _.methodOf(car, 'startEngine');
    startCar();
} else {
    console.error('Method not found.');
}

Handle Context Appropriately:

Consider the context in which the method will be executed. Ensure that the context (this binding) is preserved or set appropriately to avoid unexpected behavior.

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const calculator = {
  value: 0,
  add(num) {
      this.value += num;
      return this.value;
  }
};

const addFive = _.methodOf(calculator, 'add');

// Explicitly set context to calculator object
const result = addFive.call(calculator, 5);

console.log(result);
// Output: 5

Encapsulate Logic:

Encapsulate complex or repetitive logic within methods of objects. _.methodOf() can then be used to invoke these methods dynamically, promoting code reusability and maintainability.

example.js

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const mathUtils = {
  square(num) {
    return num * num;
  },
  cube(num) {
    return num * num * num;
  }
};

const calculate = (operation, num) => {
  const method = _.methodOf(mathUtils, operation);
  return method(num);
};

console.log(calculate('square', 3));
// Output: 9

console.log(calculate('cube', 3));
// Output: 27

📚 Use Cases

Dynamic Function Execution:

_.methodOf() is particularly useful for scenarios where the method to be executed is determined dynamically at runtime. This enables flexible and dynamic function invocation.

example.js

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const objectWithMethods = {
  method1() {
    console.log('Method 1 executed.');
  },
  method2() {
    console.log('Method 2 executed.');
  }
};
const methodName = /* ...dynamically determine method name... */ ;
const dynamicMethod = _.methodOf(objectWithMethods, methodName);
dynamicMethod();

Function Composition:

In function composition patterns, _.methodOf() can be employed to compose complex behaviors by dynamically invoking individual functions within the composition.
example.js
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```
const composeFunctions = (f, g) => _.flow(_.methodOf(window, f), _.methodOf(window, g));

const composedFunction = composeFunctions('alert', 'confirm');
composedFunction('Hello');
```

Method Delegation:

When delegating method calls between objects or modules, _.methodOf() can facilitate the seamless invocation of methods within different contexts.

example.js

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const moduleA = {
  methodA() {
    console.log('Method A executed.');
  }
};
const moduleB = {
  methodB() {
    console.log('Method B executed.');
  }
};
const delegateMethod = (moduleName, methodName) => {
  const module = /* ...retrieve module dynamically... */ ;
  const method = _.methodOf(module, methodName);
  return method.call(module);
};
delegateMethod('moduleA', 'methodA');
delegateMethod('moduleB', 'methodB');

🎉 Conclusion

The _.methodOf() method in Lodash offers a convenient solution for dynamically invoking object methods. Whether you're dealing with dynamic function execution, function composition, or method delegation, this utility method provides flexibility and versatility in JavaScript programming.

By adhering to best practices and exploring diverse use cases, you can harness the full potential of the _.methodOf() method in your Lodash projects.