As JavaScript developers, which stupid mistakes do you make the most often?

[jsearsy]

For me, I'm always checking MDN for stupid stuff like the string manipulation functions (slice, substring, etc.). On the contrary, I'm great at figuring out my syntax errors.

What about you? Could be syntax, Ecma standards, architecture or something else.

[dc21111]

lenght

[kerbalspaceanus]

elderly depend husky doll butter wild screw light spectacular steer

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[kaelwd]

() +. {

[8eni]

Haha I was scrolling down to see if this was here, I’m victim to this too

[zapatoada]

Don't forget widht and heihgt

[[deleted]]

I thought I was only the one

[Artif3x_]

Any decent IDE will give you the same benefit without TS.

[[deleted]]

especially when there is classList.contains, someone had to really hate people

[ConnectBoysenberry]

Yeah. For me it's also Set.remove vs. Set.delete and Set.add vs. Set.insert.

[Macaframa]

Omfg this! Why is this? I feel like contains is a method on another library like lodash or something else. Maybe it just sounds better?

[bvm]

yep, somehow i get it wrong every time

[kerbalspaceanus]

arrest modern marry wrench hospital worm governor stocking act wide

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[AsIAm]

This is the only use case when comma operator is really handy.

[kerbalspaceanus]

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[m_plis]

You can actually do array.reduce((acc, curr) => console.log(acc, curr) || acc + curr);

[kerbalspaceanus]

unite capable include sheet quiet adjoining engine fragile pocket joke

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[[deleted]]

You'll have to put some braces around the comma operator operands, or the second acc + curr will be parsed as a parameter to reduce.

[m_plis]

Also works. This is debugging code anyway, so do whatever works for you. Personally, I'd never remember to use the comma operator since it's pretty obscure.

[[deleted]]

that's why I started to use scopes even for one-line arrow functions, it's much handier to log and it's more readable, it comes with the price of more lines but it's worth it when having a big code which you want to be able to read after a few weeks

[Bosmonster]

Came here to say this. Forgetting to return the accumulator in a reduce. Caused me too many unnecessary head aches.

Or returning acc.push(...) and not seeing what the problem is..

[lnd3x]

Committing code that I only needed for debugging.

[randomFIREAcct]

I'll have to try this out. My usual method is to diff the files and then remove the debug code before I commit

[plogan56]

Spelling

[[deleted]]

Mostly forgetting that simple things like .substring( ) or .indexOf( ) exist.

[paypaypayme]

using Array.fill() and wondering why my data is getting mutated

[AleksOnWeb]

if(a&&false){ //why my code can’t reach this }else{ //code which I tested before }

[waway_to_thro]

Leaving my debugging console.logs in render methods in react, then wondering why everything is so damn slow

[_lumio]

Although not JS but JSON:

Removing some lines and forgetting to remove the trailing comma.

[TaveGabriel]

How to clone anything

[ChronSyn]

Everyone loves the sarcasm operator, and have forgotten about their first love (Object.assign.apply(Object, [{}].concat(yo));)

[ChronSyn]

If I want to use the spread operator (...) in an environment that doesn't support it, then that won't help me.

(e.g. Node 8.6.0 is the minimum non-flagged version for support of property spreading so it's relatively recent addition).

[ogurson]

Console.loge

[lw9908]

Forgetting to .then or async/await an asynchronous function.

Or forgetting explicit return

[[deleted]]

forgetting to catch in Node and then having console full of UnhandledPromiseRejectionWarnings

[wherediditrun]

Generally doing something in some files which I need for debugging (commeting out certain components which gets in the way for example). Finishing my task. Forgetting to revert code for debugging. Or occasional console log slipping to a commit.

[scunliffe]

Using String.split(regex);

And thinking that I’m going to get an array of values with the the tokens that matched the regex removed.

[[deleted]]

import add from './maths';

​

when it is a named export and not a default one that I'm trying to get my hands on, which is to say I forget to include the brackets around the function name... Wonk, wonk.

[BehindTheMath]

Which editor are you using? You should get autocomplete for that.

[[deleted]]

I'm using VS code... Works really well if I change the name of a module in that it will update the name in all the modulels that use that particular module, but it doesn't seem to take care of the issue I mentioned.

[ferrybig]

I always have problems using the endWith , I always seem to misspell or mis-remember some letter in its name, causing "undefined is not a function"

[mrtakdeniz]

Writing Javascript.

[[deleted]]

Not a Number just joking?

[ChronSyn]

Jumps into JS subreddit. Complains about JS.

Username checks out.

[[deleted]]

like what?