How to parse a custom date string in clj-time?

Use clj-time.format with a custom formatter, e.g., (def formatter (f/formatter "yyyyMMdd")) and (f/parse formatter "20100311"), as shown in the README. This allows handling various date formats without manual string manipulation.

clj-time deprecated, what should I use instead?

For Java 8 or later, switch to the built-in java.time API or Clojure wrappers like clojure.java-time or cljc.java-time for cross-platform support. The README recommends these alternatives due to Joda Time's deprecation.

How to add months to a date in clj-time?

Use the plus function with months from clj-time.core, e.g., (t/plus (t/date-time 1986 10 14) (t/months 1)). This provides immutable date arithmetic without side effects, as demonstrated in the examples.

clj-time or clojure.java-time, which is better?

clojure.java-time is preferred for new projects as it wraps the modern java.time API, is actively maintained, and supports ClojureScript. clj-time is legacy and deprecated, suitable only for maintaining old codebases.

Can clj-time handle time zones correctly?

Yes, it offers functions like from-time-zone and to-time-zone for timezone manipulation, and local-date for timezone-independent dates. However, it inherits Joda Time's timezone logic, which can be complex but comprehensive.

How to convert clj-time DateTime to a Java long timestamp?

Use clj-time.coerce/to-long, e.g., (c/to-long (t/date-time 1998 4 25)) returns Unix epoch milliseconds. The coercion utilities support various types like java.util.Date and SQL timestamps for interoperability.

clj-time — Clojure Date & Time Library

What is clj-time?

clj-time is a Clojure library that wraps the Joda Time Java library to provide functional, immutable date and time operations. It solves the problem of cumbersome time handling in Clojure by offering a clean API for creation, arithmetic, formatting, and comparison of dates and times. The library is now deprecated as Joda Time itself is superseded by Java Time in Java 8+.

Target Audience

Clojure developers working on applications that require robust date and time manipulation, especially those using Joda Time in legacy Java environments or prior to Java 8 adoption.

Value Proposition

Developers choose clj-time for its idiomatic Clojure interface to Joda Time's comprehensive features, reducing boilerplate and providing immutable, functional date-time operations. Its seamless integration with SQL databases via JDBC extensions is a key advantage for data-driven applications.

A date and time library for Clojure, wrapping the Joda Time library.

Use Cases

Best For

Legacy Clojure applications using Joda Time before Java 8 migration
Parsing and formatting dates in multiple custom formats
Generating sequences of dates at regular intervals (e.g., scheduling)
Performing complex date arithmetic with time zones
Working with SQL databases using DateTime objects directly
Checking date conditions like weekends or month ends in business logic

Not Ideal For

New projects using Java 8 or later where java.time is built-in and recommended
Cross-platform ClojureScript applications needing date-time handling in JavaScript environments
Teams prioritizing actively maintained libraries with modern support and updates

Pros & Cons

Pros

Idiomatic Clojure Interface

Provides a functional, immutable API that wraps Joda Time, making date-time operations more expressive and less error-prone in Clojure, as shown in the core namespace with functions like date-time and plus.

Seamless JDBC Integration

Offers protocol extensions in clj-time.jdbc to use DateTime objects directly with SQL databases, reducing boilerplate for database operations without manual coercion.

Rich Formatting and Parsing

Supports built-in ISO8601 and custom formatters for flexible date serialization, with examples in clj-time.format for parsing strings like '20100311' with custom patterns.

Comprehensive Date Arithmetic

Enables complex time manipulations such as adding months or weeks, interval management, and generating periodic sequences, detailed in clj-time.core and clj-time.periodic.

Cons

Deprecated and Outdated

Marked as deprecated in the README, with Joda Time itself superseded by Java Time in Java 8+, making it unsuitable for new development and lacking future updates.

Silent Error Handling

Inherits Joda Time quirks, such as unparse silently returning the current date/time when passed nil, leading to potential bugs without explicit checks, as warned in the README.

No ClojureScript Support

Tightly coupled to Joda Time, a Java library, so it cannot be used in ClojureScript or non-JVM environments, limiting its applicability for modern cross-platform projects.

What is clj-time?

Target Audience

Clojure developers working on applications that require robust date and time manipulation, especially those using Joda Time in legacy Java environments or prior to Java 8 adoption.

Value Proposition

Use Cases

Best For

Legacy Clojure applications using Joda Time before Java 8 migration
Parsing and formatting dates in multiple custom formats
Generating sequences of dates at regular intervals (e.g., scheduling)
Performing complex date arithmetic with time zones
Working with SQL databases using DateTime objects directly
Checking date conditions like weekends or month ends in business logic

Not Ideal For

New projects using Java 8 or later where java.time is built-in and recommended
Cross-platform ClojureScript applications needing date-time handling in JavaScript environments
Teams prioritizing actively maintained libraries with modern support and updates

Pros & Cons

Pros

Idiomatic Clojure Interface

Seamless JDBC Integration

Offers protocol extensions in clj-time.jdbc to use DateTime objects directly with SQL databases, reducing boilerplate for database operations without manual coercion.

Rich Formatting and Parsing

Supports built-in ISO8601 and custom formatters for flexible date serialization, with examples in clj-time.format for parsing strings like '20100311' with custom patterns.

Comprehensive Date Arithmetic

Enables complex time manipulations such as adding months or weeks, interval management, and generating periodic sequences, detailed in clj-time.core and clj-time.periodic.

Cons

Deprecated and Outdated

Marked as deprecated in the README, with Joda Time itself superseded by Java Time in Java 8+, making it unsuitable for new development and lacking future updates.

Silent Error Handling

Inherits Joda Time quirks, such as unparse silently returning the current date/time when passed nil, leading to potential bugs without explicit checks, as warned in the README.

No ClojureScript Support

Tightly coupled to Joda Time, a Java library, so it cannot be used in ClojureScript or non-JVM environments, limiting its applicability for modern cross-platform projects.

clj-time

What is clj-time?

Overview

Use Cases

Best For

Not Ideal For

Pros & Cons

Pros

Cons

Frequently Asked Questions

Related Projects

Found a gem we're missing?

clj-time

What is clj-time?

Overview

Use Cases

Best For

Not Ideal For

Pros & Cons

Pros

Cons

Frequently Asked Questions

Related Projects

Found a gem we're missing?