A Simple, Comprehensive Overview of Javascript | Hacker News Reader

A Simple, Comprehensive Overview of Javascript

betterexplained.com

76 pointsColinWright15 comments

> parseInt("123") // base 10 => 123

The radix is not always 10 by default, it's implementation dependent and sometime it even depends on the number to be parsed. "8" will be parsed in base 10, "08" in base 8. Always specify the radix [1]

[1] https://developer.mozilla.org/en-US/docs/Web/JavaScript/Refe...

I think a really good addition to the blog post would be a link to an article/blog post that explains more in-depth the different topics shown. For instance, when you discussed Objects, a link to http://javascriptissexy.com/javascript-objects-in-detail/ would have been very useful. Javascript has a lot of weird edge cases and peculiarities that newcomers should read about.

Other than that, awesome post. I always love just seeing the code vs. reading about it in a book. I find it's easier to learn that way, especially when the language you're coming from has a lot of similarities.

EDIT: To clarify, I have no affiliation with 'JS is Sexy', I just think the lessons/tutorials Richard Bovell writes are awesome!

(Author here) Thanks for the feedback! I originally wrote this in 2007 when I was diving into Javascript to build instacalc.com.

I agree with the examples vs. trying to read in a book. Books often get in their own way, trying to overgeneralize: just show me the code! If I already know how to program, having 5-10 reference examples of every language feature should be enough. You don't need to explain what a conditional is, etc.

I'll put in a link to that object deep dive :).

Don't throw strings. Use the Error object.

I don't see why it really matters most of the time, especially in one-off javascript scripts.

Error objects have stack traces in modern engines, which is very helpful for debugging. Strings do not.

That seems like poor design on the engines' part.

Because someone will come along and copy and paste your broken code and put it into something else and now more people have to deal with it. Just take the steps to make it not suck from day 1 :)

Eval is evil.

Don't pass a string as first argument to setTimeout.

But if you really need eval ( i do sometimes yes ) , use scoped evals with a function constructor.

    var myEval = new Function("my().stuff().to().eval();");

    myEval();

Simple and Comprehensive? Aren't those opposites in this case?

In "Javascript Classes," is the public function self.setName supposed to be this.setName?

typeof is an operator not a function

Multi-line strings are non-standard.

> Redirect if javascript disabled: <noscript><meta http-equiv="refresh" content="0; URL=http://example.com/noscript.html"/></noscript>

Dont do that, redirect when javascript IS enabled(if it is a SPA). or you'll take a huge SEO hit. your website should be usable without javascript anyway. the SPA itself doesnt care about SEO because it is not crawlable anyway.

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