There are situations when you need to initialize object without props. How do you manage that it Typescript? Let’s consider the example below. First, we declare the object and initialize it to an empty object. 1 const planet = {}; Then, we add the props - 1 planet.

A simpler way to do curry functions in Javascript. We have previously seen currying in Javascript. A simple form and application of that concept is demonstrated below - 1 2 3 const addThem = add.curry(2); const addTotal = addThem(1); console.log("addTotal: ", addTotal); // 3 Or, we could avoid a external function or library and curry using bindings .

Beware of using implicit returns in arrow functions. Consider the below example of a simple arrow function. It returns a simple variable. In the absence of any other statement in the function body, a simple mention of x will return the value of x. 1 2 3 const getStuff = x => x; console.

Use onclick rather than submit in HTML forms. A typical HTML form has a few fields and a button to submit the data to some back-end server. And, the typical way to do the form submission is through the submit method. 1 2 3 4 5 <form action="/helloMessage.php"> <input type="text" id="name" /><br /> <button type="submit"></button> </form> On clicking the button, the page will submit data to helloMessage.

How can you use await without an async function? Don’t click or proceed further if you are not into practical jokes. Say, you try using await in a “normal” function or directly within a module.. 1 2 3 4 5 6 7 function getWeather(loc) { const weather = await fetchWeather(loc); return weather; } // SyntaxError: await is only valid in async function You receive a compilation error that await can be used only in async function.

Generate Fibonacci series with generators and feel good about yourself. Previously you have seen how the totally practical example of generating Fibonacci series was breathing fire with memoization, and may have also come across using loops or recursion to solve the same problem. But, there is no fun in all that - this is real-life and we have to “generate” fun (yep, there we go again).

Previously, we have talked about all things being an object in Javascript. But to what extent can we apply this to our beloved functions. You can see this almost everywhere with the below syntax - 1 2 3 4 5 6 const getSum = (x, y) => { return x + y; }; console.

What are generators and how can I use them? How do you write loops in Javascript - Simple for/while? Recursion? In other less exciting ways? How do you throttle and control function execution? Debounce function? Build your own? What if you could produce the right mix of reusable functions, looping and throttling in one go?

Is there really a problem with NPM use? Short answer: no. Long answer: it’s complicated. I am nothing but thankful for the tonnes of NPM packages. I would never have built web applications that could support thousands of users all by myself without all those hundreds of packages. There are thousands of developers (if not millions) who do much better than what I could.

Flatten recursive arrays using Array.flat(). We have seen how to flatten arrays before. Array.flat() is quite useful to flatten arrays in one statement and output a simpler array. But, what about situations where you do not know the depth of array hierarchy - 1 const nums = [[1, 2], [3, 4], [[5], [6]], [[[7]]]]; Fear not.

Remember to filter your arrays before doing array-wise operation. Filtering falsy values must be the first operation even if you do not have specific filtering requirements. Consider this array - 1 const nums = [1, 3, 5, undefined, 7, 9, null]; If you are in control of the data source, you can very well expect to filter only when necessary.

Can you use the Date object without brackets? Yes, apparently - to a friend’s delight and my chagrin. I should know better than to rely on my somewhat shaky Javascript knowledge. This is the format for a sane Date code.. 1 2 3 const today = new Date(); console.log(today); // 2019-08-23T09:31:12.

Load external scripts asynchronously in Javascript. We have seen about loading functions asynchronously in Javascript. But, what about the scripts that you load from other files, CDNs or other external sources You can do a simple async to load scripts without impacting the loading speed as perceived by the user.