Lodash _.eq() Lang Method

Posted in lodash Tutorial

Updated on Oct 30, 2024

By Mari Selvan

👁️ 20 - Views

⏳ 4 mins

💬 1 Comment

Photo Credit to CodeToFun

🙋 Introduction

In the world of JavaScript development, precise comparison of values is a fundamental aspect. Lodash, a versatile utility library, provides the _.eq() method, a powerful tool for performing strict equality checks between two values.

This method goes beyond the capabilities of the native JavaScript === operator, offering additional features for nuanced comparison scenarios.

🧠 Understanding _.eq() Method

The _.eq() method in Lodash is designed to perform a strict equality check between two values. While similar to the native JavaScript === operator, _.eq() provides enhanced functionality for specific use cases, making it a valuable addition to a developer's toolkit.

💡 Syntax

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

syntax.js

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_.eq(value, other)

value: The first value to compare.
other: The second value to compare.

📝 Example

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

example.js

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const _ = require('lodash');

const value1 = 'hello';
const value2 = 'hello';
const value3 = 'world';

console.log(_.eq(value1, value2)); // Output: true
console.log(_.eq(value1, value3)); // Output: false

In this example, _.eq() is used to compare two string values, demonstrating its ability to determine strict equality.

🏆 Best Practices

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

Strict Type Comparison:

_.eq() performs strict type comparison, similar to the === operator. Ensure that you intend to compare values of the same type, especially when dealing with variables of dynamic types.
example.js
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```
const numberValue = 42;
const stringValue = '42';

console.log(_.eq(numberValue, stringValue)); // Output: false
```
Handling NaN Values:

Unlike the === operator, _.eq() considers two NaN values as equal. This behavior can be useful when dealing with scenarios involving NaN.
example.js
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```
const nanValue1 = NaN;
const nanValue2 = NaN;

console.log(_.eq(nanValue1, nanValue2)); // Output: true
```
Arrays and Objects:

When comparing arrays or objects, _.eq() performs a deep equality check, ensuring that the contents are identical.
example.js
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```
const array1 = [1, 2, 3];
const array2 = [1, 2, 3];

console.log(_.eq(array1, array2)); // Output: true
```

📚 Use Cases

Handling Type-Sensitive Scenarios:

In scenarios where strict type comparison is crucial, such as when validating user input or configuration settings, _.eq() ensures that values are not only equal but also of the same type.
example.js
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```
const expectedType = 'number';
const userInput = '42';

if (_.eq(typeof userInput, expectedType)) {
  console.log('User input is a number.');
} else {
  console.log('User input is not a number.');
}
```
Dealing with NaN Values:

When dealing with calculations that may result in NaN values, _.eq() can simplify checks for NaN equality.
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```
const result = Math.sqrt(-1);

if (_.eq(result, NaN)) {
  console.log('Result is NaN.');
} else {
  console.log('Result is not NaN.');
}
```

Deep Equality Checks:

For arrays or objects where a deep comparison is required, _.eq() ensures that all elements or properties are strictly equal.

example.js

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const object1 = { a: 1, b: { c: 2 } };
const object2 = { a: 1, b: { c: 2 } };
const object3 = { a: 1, b: { c: 3 } };

console.log(_.eq(object1, object2)); // Output: true
console.log(_.eq(object1, object3)); // Output: false

🎉 Conclusion

The _.eq() method in Lodash provides a robust solution for performing strict equality checks in JavaScript. Whether handling type-sensitive scenarios, dealing with NaN values, or ensuring deep equality in complex data structures, _.eq() offers a versatile and reliable tool for developers.

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