The Math PI constant in javaScript contains a constant value of PI. The value of PI is a constant ratio where if the diameter of a circle is equal to one then the circumference of that circle is equal to PI.

So the use of the PI constant will come up a lot with expressions that have to do with circles, arcs, angles, and just about anything else where a constance variable for the value would come into play. There are many practical use case examples for PI in javaScript and of course in programming in general. There are many simple formulas some of which you might all ready be familiar with that have to do with getting the circumference or area of a circle.

Many of the other Math methods in javaScript accept radians rather than degrees when it comes to using an angle as an argument, so it makes sense to have at least a little experience working with some basic expressions using Math PI. So then just for the sake of getting used to the deal with PI and Radians as a unit of measurement for angles, it would make sense to start playing around with a few simple expressions that make use of Math.PI if you have not done so before hand.

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In client side javaScript there is the onunload event that can be used o attach an event handler that will fire when a user leaves a page. This can be used to save something to local storage such as updating a time stamp value or something to that effect that should happen when the user navigates away from a page or the site completely.

The onunload event should be attached to the window object rather than an element of one sort of another as this is an event that will not happen with a single element, but when the whole page is unloaded. So it can be though of as the opposite of the onload event that will fire when a page has finished loading. So lets take a moment to look at a few quick examples of the onunload event in action to get a better sense as to why this event is helpful in many situations that might call for its use in a project.

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The lodash sorted uniq method can be used to remove all redundant copies of an element from an array. This is one of many methods in lodash that seem a little redundant, or present some kind of functionality that can easily be done with just native javaScript by itself. In any case this will be a quick post on creating a new array with repeat elements removed using lodash sortedUniq method, along with other lodash solutions for this, and vanilla javaScript alternatives to this method.

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When first starting out with javaScript it is only natural to go through a phase where a developer needs to become more familiar with how to go about working with arrays in javaScript. There is just simply knowing how to create them for starters, but then there is getting elements from them in a why in which the arrays are mutated in place, as well as not doing so when it comes to working with a source array. There are many methods of interest when it comes to just simply geting one or more elements from an array in javaScript, but maybe one of the first methods one will become aware of is the js array pop method.

The js array pop prototype method will remove and return the last element in an array. This method works okay for what it is intended to be used for, however it might not always be the best choice. For example what if it is the first element that is to be removed and returned, and also what about injecting elements while one is at it? So this post will center on the use of the js array pop method, but also other ways of getting one or more elements from an array such as shift, splice, and just the use of the bracket syntax with an index number.

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The home directory or user folder in an operating system is a folder for the current user. This folder is then a good place to park any kind of user specific settings or data when making a nodejs application. So then there should be some kind of standard way of getting a path to this folder in a way that will work across different operating systems. With that said there is in the nodejs built in os module, to which there is a method called homedir.

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