Lodash _.isNumber() Lang Method

Posted in lodash Tutorial

Updated on Oct 30, 2024

By Mari Selvan

👁️ 32 - Views

⏳ 4 mins

💬 1 Comment

Photo Credit to CodeToFun

🙋 Introduction

In the landscape of JavaScript development, robust data validation is essential to ensure the integrity and reliability of code. Lodash, a versatile utility library, offers a suite of functions to simplify common programming tasks. Among these functions is _.isNumber(), a Lang method designed to determine whether a given value is a JavaScript number.

This method aids developers in building more resilient and error-resistant code by providing a straightforward means of checking numerical data.

🧠 Understanding _.isNumber() Method

The _.isNumber() method in Lodash is a simple yet powerful tool for validating whether a value is a number. This can be particularly useful when handling user input, API responses, or any scenario where data types need to be accurately assessed.

💡 Syntax

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

syntax.js

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_.isNumber(value)

value: The value to check.

📝 Example

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

example.js

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const _ = require('lodash');

const numericValue = 42;
const nonNumericValue = 'Hello, World!';

console.log(_.isNumber(numericValue)); // Output: true
console.log(_.isNumber(nonNumericValue)); // Output: false

In this example, _.isNumber() correctly identifies the numeric value as a number and the non-numeric value as not a number.

🏆 Best Practices

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

Strict Type Checking:

When using _.isNumber(), consider whether you need strict type checking. By default, this method performs loose type checking, meaning it returns true for values that can be coerced into numbers. If strict type checking is required, additional checks may be necessary.
example.js
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```
const numericString = '42';
console.log(_.isNumber(numericString)); // Output: true (loose type checking)

console.log(Number.isNaN(numericString)); // Output: true (strict type checking)
```
Handling NaN (Not a Number):

Be aware that _.isNumber() returns false for NaN values. If your use case involves distinguishing between NaN and other non-numeric values, consider additional checks using isNaN().
example.js
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```
const nanValue = NaN;
console.log(_.isNumber(nanValue)); // Output: false

console.log(Number.isNaN(nanValue)); // Output: true
```
Numeric Validation in Conditional Statements:

When using _.isNumber() in conditional statements, consider potential edge cases and whether a fallback behavior is needed for non-numeric values.
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```
const userInput = /* ...get user input... */ ;

if (_.isNumber(userInput)) {
  console.log('Valid numeric input:', userInput);
} else {
  console.log('Invalid input. Please enter a number.');
}
```

📚 Use Cases

User Input Validation:

When dealing with user input, especially in forms or interactive applications, _.isNumber() can be employed to validate whether the entered data is a numeric value.
example.js
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```
const userInput = /* ...get user input... */ ;

if (_.isNumber(userInput)) {
  console.log('Valid numeric input:', userInput);
} else {
  console.log('Invalid input. Please enter a number.');
}
```

API Response Handling:

When working with external APIs, validating numeric data in the received responses is crucial. _.isNumber() can assist in ensuring the expected data types.

example.js

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const apiResponse = /* ...fetch data from API... */ ;

if (_.isNumber(apiResponse.value)) {
  console.log('Numeric value from API:', apiResponse.value);
} else {
  console.log('Unexpected or non-numeric value in API response.');
}

Data Processing and Filtering:

In scenarios involving data processing or filtering, _.isNumber() can be utilized to selectively process or filter out numeric values.

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const dataToFilter = [42, 'apple', 23, 'orange', 17];
const numericValues = _.filter(dataToFilter, _.isNumber);
console.log('Numeric values:', numericValues);
// Output: [42, 23, 17]

🎉 Conclusion

The _.isNumber() Lang method in Lodash provides a simple yet effective way to check whether a given value is a JavaScript number. Whether you're validating user input, handling API responses, or filtering data, this method offers a valuable tool for maintaining data integrity in your JavaScript projects.

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