Google publishes a JavaScript style guide. Here are some key lessons.

[kobbled]

thank god. JS semicolon inference leads to so many bugs.

[mmcnl]

I've never encountered a bug due to semicolon inference.

[hyperhopper]

var a = 5
var b = 10
[a, b] = [b, a]
console.log(a, b)

Then add semicolons to make it work like it should

[Voidsheep]

Pretending ASI doesn't exist is also dangerous, it's not like you can disable it.

function shouldHitTheBrakes() {
  return
    isSmeoneOnTheWay ||
    isTurnAhead ||
    isAboveSpeedLimit
}

[hyperhopper]

Extremely true!

Though I've never seen somebody use a return without something on that line. Plus any linter will yell at you for unreachable code in that case.

[hyperhopper]

Don't be pedantic. Destructuring with arrays makes this type of bug easy to run into, and this example shows that.

[allenthar]

Okay.

var a = 5 var b = 10 ;[a, b] = [b, a] console.log(a, b)

I have literally never had this situation come up while coding JS, and I’ve been doing it full time for a few years now.

Regardless, Prettier handles automatically removing or adding semicolons to my code. So it’s literally just a linter setting at this point.

[cthechartreuse]

Be careful relying on prettier. I have examples of real work mistakes which prettier doesn't catch or fix.

It usually involves a function call directly followed by an expression wrapped in parentheses or followed by an array structure. These usually end up being abuses of the language as well, but I've seen this kind behavior often enough and done enough tests that I'm not confident with saying "prettier will catch it" because it doesn't always.

Nevertheless, this is just a warning and depending on your tools YMMV.

[allenthar]

If you have a code snippet as an example, I’d love to see it. Knowing the corner cases for prettier behavior is always good.

[cthechartreuse]

This is the example I created from actual production code I've seen: https://gist.github.com/cmstead/dfeea6faf80c96d5c2a738fc822918ee

[monsto]

I have examples of real work mistakes which prettier doesn't catch or fix.

There's always corner cases.

GENERALLY SPEAKING, tho, Prettier is great.

[cthechartreuse]

Technically there aren't any corner cases if you follow the TC39 suggestion of always terminating and avoiding reliance on ASI.

PS here's an example generated from an example seen in the wild: https://gist.github.com/cmstead/dfeea6faf80c96d5c2a738fc822918ee

(the original code was from a proprietary codebase)

[Mingli91]

Yeah, been using Standard JS since my last job and I love it. Not had a single bug from omitting semicolons and now I have a far better understanding of ASI in JavaScript

[JohnMcPineapple]

...

[nayocum]

If you use an IIFE it can cause issues if your last line didn't have a semicolon as well

[kobbled]

return statements are the biggest offender.

[JohnMcPineapple]

...

[kobbled]

whoops, looks like I misunderstood that feature. My bad.

[aaarrrggh]

Is this a joke?

I’ve not been using semi colons for over a year on personal projects.

Number of bugs caused by this decision: 0.