Check if a given object has a specified property. You can either use non-enumerable props or hasOwnProperty. Consider the below code - 1 2 3 4 Object.prototype.awesomeness = 42; const earth = {}; console.log(earth["awesomeness"]); // 42 We have defined a prototype that gets attached to any object. Therefore the prop defined by prototype is attached to the object as well.

Use Array.some() and Array.every() to check whether an array has elements that satisfy the given criteria. Consider the below array - 1 const nums = [3, 5, 6, 1, 2]; You can check whether the elements satisfy a specified criteria with below code - 1 2 console.

Often my server DB functions return the data in JSON format with all fields and values thrown in. 1 const alphaNum = { a: 1, b: 2, c: 3, d: 4, e: 5 }; When we use charts (or even tables), this needs to be converted to an array of arrays.

Initializing objects can be a pain. You may end up with multiple checks if you are trying to set a specific prop in the object path to a pre-defined value. For e.g. set color of a Kawasaki bike to ‘blue’. To do this we have to traverse through the object path from the root through color.

Use array filters to remove duplicates in an array. We have seen how we could use sets or an intermediate object in a loop to eliminate duplicates within array.There always is a better way of doing things. Why not use filter to make the code more readable and not use set at the same time :) ?

Are you doing array search using the old school for-loops? Time to change, kid. Consider this array - 1 2 3 4 5 const fruits = [ { name: "apple", color: "red" }, { name: "orange", color: "orange" }, { name: "pear", color: "green" } ]; To search for a specific value -

There is a really cool way to do group by in an array using reduce. The problem statement - you have an array of objects and need to create different arrays based on similar attributes. This is very similar to the SQL group by statement. Consider the example array -

How do you maintain secrets on the client-side? In one sentence - there are no secrets client-side. If you don’t want anyone to know about the secret, you should not send it to the client. The need for secrets Client may need user ids/passwords, API keys, API secrets etc. None of them can be trusted to the client.

There are multiple ways to convert a given string to a number - so, which one to use and where? You would have also seen the more generic post on how to cast value from one type to another. But it may not be so apparent on which option to pick when you need to get numbers from a given string.

You can easily introduce default values for the arguments passed to a function. Consider this function - 1 2 3 function sayHello(name) { return `hello ${name}`; } Calling this function without arguments will provide a not-so-pretty string. 1 console.log(sayHello()); // hello undefined Even if someone had an existential crisis, I doubt they will like to be called ‘undefined’.

We have a string.toLowerCase() and string.toUpperCase() in Javascript, but no out of the box function to convert to title case. Fear not if you are in that pickle - it is quite easy. 1 2 3 4 5 6 7 8 9 function ConvertTitleCase(str) { const strArr = str.toLowerCase().split(" "); for (let i = 0; i < strArr.

There are many types of for loops for an array - which should you use? How will you balance performance vs. code readability? Is that even a valid question? Let’s see a few cases. We will be seeing these distinct for loops today - for for-in forEach Note that the performance can be safely ignored for one off loops that do not hold up the user.

Use these two quick ways to get a webserver up and running from any folder. 1. Use http-server Install http-server. 1 npm install http-server -g Navigate to any folder where you need a quick web server and start server. 1 2 cd client/dist http-server You can even proxy requests to a back-end server where required.