#tc39

I'll be talking about standardizing signals in TC39. Immediate mode wipes out the whole screen and writes a new one, while retained mode changes only what is necessary. Signals represent a cell of data that can change over time. The correct solution is to topologically sort dependencies and evaluate them in a coherent order. Standard signals allow for code sharing across frameworks and the creation of reusable infrastructure. The signal API is designed to be wrapped by different frameworks. Standards can achieve more portability and reduce the need to lock into specific ecosystems. The API includes a watcher, a set of signals being observed, with a synchronous callback made when the first member becomes potentially dirty. The speaker discusses how signals relate to state management libraries in React and mentions the potential for signals to become a web standard in the future.

I'll speak today about the Temporal proposal, which adds modern date and time handling to JavaScript. Temporal is an API that'll be available in browsers soon and will add a built-in library for dates and times, avoiding the need for external libraries like Moment. It offers strong typing with different types for different data, such as calendar dates with or without time. Temporal objects are immutable and designed to work with JavaScript's internationalization facilities. It addresses deficiencies in the global Date object and introduces types like instant and plain types for accurate representation of time and dates across time zones. With the old Date, representing a date without a time can be problematic, especially in time zones where midnight is skipped due to daylight saving time. Temporal introduces types like PlainDate, PlainTime, PlainYearMonth, PlainMonthDay, and ZonedDateTime to accurately represent different scenarios. Additionally, there is a type called Duration for arithmetic operations and unit conversion. Now that I've introduced you to the cast of characters in Temporal, it's time to show how to accomplish a programming task. We'll start with an easy task: getting the current time as a timestamp in milliseconds using the instant type. To convert between Temporal types, you can either drop or add information. The toZonedDateTime method is used for conversion and requires adding a time zone and a time. Although Temporal objects are immutable, you can create new objects with replaced components using the with method. Migrating from the old Date object to Temporal offers a more reliable solution and avoids potential bugs. Check out the documentation for more details and enjoy using Temporal in your codebase!

Welcome to the future features of JavaScript, including proposals for array operations, throw expressions, records and TPUs, pipeline operators, and more. The talk covers the introduction of type assertions for imported files, non-mutating array operations, and the simplification of error handling. It also explores the concept of immutability with records and TPUs, and the use of the pipeline operator to simplify code. Other proposals include Map.implace, IteratorHelper, slice notation, type annotations, Array UNIQBY, number ranges, and the Function 1 proposal.

The Talk discusses various proposals for the next version of ECMAScript (ES Next) and the TC39 process. It covers features such as binding syntax, shorthand property assignments, pattern matching, async match, operator overloading, and more. These proposals aim to simplify code, make it more readable, and introduce new functionalities. The Talk also addresses questions about the committee's decision-making process and the experience of being part of the TC39 committee.