Sparse array destructuring in JavaScript
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Sparse array destructuring in JavaScript
1–10 of 18 posts
Re: Sparse array destructuring in JavaScript
#2I’d flag this if I saw this in a code review. It’s to cute and hard to see what’s happening. Would much rather just see someone prefix with an underscore if they don’t need the variable (const [id, _email, name] = loadUserInfo(…); is preferable to const [id, , name]).
Re: Sparse array destructuring in JavaScript
#3I code typescript every day. I don't really hate javascript. This is terrible.
Re: Sparse array destructuring in JavaScript
#4It's called "array destructuring" because you're destructuring _arrays_, but this is treating arrays like _tuples_. If you're storing more than 3 (really 2) pieces of information about a single thing in a tuple, you're almost certainly misusing tuples. Why would you store a payment record, for instance, in a tuple of the form `[customerEmail, cardLast4, amount, currency, timestamp]` when you could just use an object, have consistent names that self-document the data structure, and never need to think about the ordering of elements in tuples?
This is really only even marginally appropriate if you want to do something like this:
return Object.entries(myObject)
.filter(([, value]) => value % 2 === 0)
.map(([key, value]) => `${key} has even value ${value}`);
Re: Sparse array destructuring in JavaScript
#5I'd at least place an underscore as is common in other languages
let [one, _, three, _, five] = nums
edit: I guess you can't do that in JS, so
let [one, _two, three, _four, five] = nums
Re: Sparse array destructuring in JavaScript
#6It's called "array destructuring" because you're destructuring _arrays_, but this is treating arrays like _tuples_. If you're storing more than 3 (really 2) pieces of information about a single thing in a tuple, you're almost certainly misusing tuples. Why would you store a payment record, for instance, in a tuple of the form `[customerEmail, cardLast4, amount, currency, timestamp]` when you could just use an object,…
The rare case for me is when you really care about size. The destructured variables can be renamed by the minifier while an object will keep the property names.
Re: Sparse array destructuring in JavaScript
#7Alternative:
let { 0: one, 2: three, 4: five } = nums;Re: Sparse array destructuring in JavaScript
#8I’d flag this if I saw this in a code review. It’s to cute and hard to see what’s happening. Would much rather just see someone prefix with an underscore if they don’t need the variable (const [id, _email, name] = loadUserInfo(…); is preferable to const [id, , name]).
Why on earth would you prefer they create variables that aren't used.
Learn the language.
Re: Sparse array destructuring in JavaScript
#9I’d flag this if I saw this in a code review. It’s to cute and hard to see what’s happening. Would much rather just see someone prefix with an underscore if they don’t need the variable (const [id, _email, name] = loadUserInfo(…); is preferable to const [id, , name]).
Unfortunately eslint would likely flag this as unused vars, so typically you would not do this as you've described. Object destructuring is a bit more forgiving and can be a nice alternative: const {id, name} = loadUserInfo() - assuming you wrote loadUserInfo and are in control of the return value.
Re: Sparse array destructuring in JavaScript
#10Alternative: let { 0: one, 2: three, 4: five } = nums;
That's nuts!