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So libraries can be really useful,

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axios was really useful,

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Lodash also is really useful here.

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Now still there are a couple of things you should keep in mind when working with libraries, for one

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keep in mind that for example Lodash here, if you add it like this, includes a lot of functionality which

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you never use.

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We only use the difference method here and yet we still import all the other features as well,

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that means that users of our application will download all that code even if we just use one feature.

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We can see the effect if we reload our page, you see the Lodash package here has 24kb.

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Now obviously that's not that big but it's way bigger than the rest of our application, so that can be

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a downside, you're downloading way more than you might need and that could slow down the initial loading

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time of your application which matters a lot if your application primarily targets people in areas of

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the world with poor internet connection.

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So that's one thing to keep in mind,

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you might include a lot of overhead.

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That being said however, it is worth pointing out that many libraries allow you to import them in different

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ways,

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for example Lodash gives you a core build which only comes with some of the features, which is way

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smaller or in more advanced project setups which we'll also cover later in the course,

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you even have other capabilities of basically just importing parts of a library and then stripping out

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the parts which you don't need.

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This project setup is not capable of doing that but we'll have a look at our project setups later in

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the tooling section. So you can mitigate this problem but still, it is something to keep in mind, also

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because not all libraries allow you to be as selective as I just described.

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In addition to that, you also want to make sure you are working with libraries which are secure and well

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maintained, let's use axios here.

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It's open source which means everyone can view the source and everyone can collaborate.

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Now typically when you want to work on the code and share your edited code, of course it's validated

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before it's merged into this codebase, so you can't easily hack this library, instead open source typically

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actually improves code quality and security because more people are looking over it and working on it.

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So having open source is generally good but you want to make sure that the library you're using is also

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actively maintained, so that if there are bugs, bugs that break your application or security issues which

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of course also are very important, that they are fixed in time.

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Now an indicator for that for example is to view the last commit,

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this basically means when the code was edited the last time.

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If this is two years old, then it looks like it's not actively maintained anymore,

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two days, a week, a month, that is pretty active.

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You can also check the releases page on Github to find out how often new versions are released and if that

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is fairly regular, let's say once a year, twice a year,

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then this also seems to be actively maintained,

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for example axios here had its last release on June 1st at the point of time I'm recording this, which

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is not too far in the past.

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You can also check out the issues here and it's quite normal that every package which is popular has

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a lot of issues to get an overview if

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there are any big problems, though the sheer number here shouldn't be an indicator,

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as I said the more popular packages, the more issues it will have, not all issues here have to be real

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issues let alone big issues.

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So these are some of the things you want to watch out for.

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You can also judge the popularity of a package by looking at the Github stars, axios has a lot of them.

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if you also have a look at some other packages, some other projects in Github, you will see that they

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typically have way less stars than that.

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So these are some of the things you want to consider when choosing a package,

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why are these things important?

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Because for one you of course don't want to add a package which might open up a security hole, that's

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very important that you don't do that

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and in addition even if it's not insecure, if it has bugs which are not getting fixed because it's not

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maintained anymore, then your application might break and all of a sudden, the package you're depending

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on is not getting updated anymore, so your application is broken and now you have to find an alternative

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or write the logic which you previously used from the package on your own to make your application work

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again.

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So these are some considerations you should keep in mind and with all of that in mind though, there is

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nothing that speaks against using third-party libraries,

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they can really make your life easier and in modern development, it's normal to use typically a couple

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of external libraries in every project you're working on.