🥳 Signals To Become Part Of Javascript

The Ecmascript’s TC39 commitee will discuss working on Signals standardization this month. It’s not an April Fool’s joke. Signal based reactivity may become a standard feature of Javascript

What Is Reactivity ?

Over the last years reactivity became a backbone of all modern frontend frameworks and the React library.

For the people unfamiliar with frontend development it may be an awkward concept at first because it changes the regular, from top to bottom, from caller to calle, sequential workflow.

In the reactivity paradigm, data update automatically when things change, just to show you a plain pseudocode:

           effect: console.log(x+2)
x = 2
x = 3

          

According to the regular flow of code the output of this would be displaying NaN or something similar because x is not defined, and nothing more than that.

Based on the reactive paradigm an app could display NaN but also 4 and 5 once the value of x changes, without any special effort from the programmer.

I totally simplified the topic, just to give an idea for people who don’t know anything about reactivity.

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Just to point out it’s very useful in many cases in frontend development. For example to display the user interface. A framework can recognize when a variable changes to update the user interface. For example when you display a real time thermometer.

The use cases go beyond that, and reactivity is used in almost all frontend frameworks. There’s even a reactive jQuery library.

How Reactivity Is Accomplished?

One nice example of practical reactivity is a spreadsheet. When you put a calculation into a spreadsheet based on other cell’s value, you don’t have to update the calculation. The spreadsheet app automatically detects the change and update all values based on calculations referencing the modified cell.