Lodash _.isDate() Method

Syntax, Parameter and Return Value

Syntax: 

_.isDate(value)

Parameters:

value: The value to check.

Return Value: 

(boolean) - Returns true if value is a Date object, else false.

Examples 

Basic Date Check:

• JavaScript

JavaScript

var _ = require('lodash');

console.log(_.isDate(new Date())); 

console.log(_.isDate('2021-01-01')); 

console.log(_.isDate(Date.now())); 

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 Output: 

true
false
false

Demonstrates checking if various values are Date objects.

Validating Date in Function Parameters:

function processDate(date) {
  if (!_.isDate(date)) {
    throw new Error('Invalid date');
  }
  // Date processing logic
}

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Shows how to validate that a function parameter is a date.

Filtering Dates in an Array:

• JavaScript

JavaScript

var mixedArray = [new Date(), '2021-01-01', new Date('2021-01-02')];

var dates = _.filter(mixedArray, _.isDate);

console.log(dates.length); 

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Output: 

2 (only Date objects are included)

An example of filtering Date objects from an array of mixed values.

Conditional Logic Based on Date Type:

var data = { eventDate: new Date() };
if (_.isDate(data.eventDate)) {
  // Handle date-specific logic
}

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Demonstrates using _.isDate() for conditional logic based on the type of a property.

Frequently Asked Questions

Can _.isDate() detect invalid or undefined dates?

_.isDate() checks if a value is a Date object, but it doesn't validate whether the date is valid. For instance, new Date('invalid-date') is still considered a Date object.

How does _.isDate() differ from using instanceof Date?

_.isDate() and using instanceof Date are similar in functionality. The primary difference is that _.isDate() is part of the Lodash library, which provides consistent behavior across different environments.

Is _.isDate() necessary for simple date checks?

For basic checks, instanceof Date is often sufficient. However, _.isDate() can be a more readable and consistent choice, especially when Lodash is used for other utilities in a project.

Conclusion

Lodash's _.isDate() method provides a simple and effective way to verify if a value is a Date object. It is a useful utility for ensuring correct handling of date values in various operations, such as formatting, arithmetic, or comparison.

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