"Destructuring allows you to bind a set of variables to a corresponding set of values anywhere that you can normally bind a value to a single variable" ("Common Lisp the Language").
Questions tagged [destructuring]
1338 questions
10
votes
1 answer
*why* does list assignment flatten its left hand side?
I understand that list assignment flattens its left hand side:
my ($a, $b, $c);
($a, ($b, $c)) = (0, (1.0, 1.1), 2);
say "\$a: $a"; # OUTPUT: «$a: 0»
say "\$b: $b"; # OUTPUT: «$b: 1 1.1» <-- $b is *not* 1
say "\$c: $c"; # OUTPUT: «$c: 2» …
codesections
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10
votes
1 answer
Destructuring/list assignment with the `has` declarator
[I ran into the issues that prompted this question and my previous question at the same time, but decided the two questions deserve to be separate.]
The docs describe using destructuring assignment with my and our variables, but don't mention…
codesections
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10
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1 answer
Why does JS desctructuring assignment work with numbers
As the title says, why does this code not throw a SyntaxError? I thought you could only destructure Objects
const {
a,
b
} = 0;
console.log(a, b); // undefined, undefined
Luka Prebil Grintal
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4 answers
Destructure/access a property that may or may not exist on an object union type
I get the following errors:
type Union = { type: "1"; foo: string } | { type: "2"; bar: number };
function doSomething = (object: Union) => {
const { foo } = object
// ^ TS2339: Property 'foo' does not exist on type 'Union'.
…
Michal Kurz
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10
votes
4 answers
Destructure object into an array
I have this object
const foo = {
a: 'kitten',
b: 'puppy',
c: 'lion'
};
Destructuring it into variables goes like this
const { a, b, c } = foo;
Is there a one-liner how to desctructre this into an array, so that the result ist
const…
four-eyes
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How can I do object destructuring with condition?
So I have:
// some function that returns two arrays ..
getArrays() {
return {
arr1: [...],
arr2: [...]
};
}
// and then ..
let arr1 = [];
let arr2 = [];
if (someCondition) {
{ arr1, arr2 } = getArrays();
}
// here we expect arrays,…
pesho hristov
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10
votes
5 answers
ES6 destructuring object assignment function parameter default value
Hi I was going through examples of object destructuring use in passing function parameters here Object Destructuring Demo
function drawES6Chart({size = 'big', cords = { x: 0, y: 0 }, radius = 25} = **{}**) {
console.log(size, cords, radius);
//…
Shailesh Vaishampayan
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1 answer
Typescript Object destructuring results in "Property assignment expected."
I am transitioning a project from Babel to Typescript and receive the following compiler error:
error TS1136: Property assignment expected.
from code that looks like this:
var auth = {...this.props.auth};
This code previously worked fine under…
Rick
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10
votes
2 answers
Is is possible to destructure a clojure vector into last two items and the rest?
I know I can destructure a vector "from the front" like this:
(fn [[a b & rest]] (+ a b))
Is there any (short) way to access the last two elements instead?
(fn [[rest & a b]] (+ a b)) ;;Not legal
My current alternative is to
(fn [my-vector]…
RubenLaguna
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10
votes
2 answers
Any good way to declare unused variables in destructuring-bind?
I can't figure, is there any way to put something like _ in erlang, for "unused value" in destructuring-bind?
For example there we have something like that:
(destructuring-bind ((_SNIPPET
(_TITLE . title)
…
sheikh_anton
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9
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1 answer
Destructuring assignment in object creation
As with my previous question, this is an area where I can't tell if I've encountered a bug or a hole in my understanding of Raku's semantics. Last time it turned out to be a bug, but doubt lightning will strike twice!
In general, I know that I can…
codesections
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9
votes
2 answers
Array Destructuring Skipping Values
My airbnb styleguide told me I should use Array Destructuring for the assignment below.
const splittedArr = [1, 2, 3, 4, 5]
const result = splittedArr[1];
So I wrote it like this using skipping values , to get the second element.
const…
Aalexander
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9
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1 answer
How to destructure an object without one key
I have an object like obj = { test1: 'sth', test2: 'sth', label: 'sth' }.
And I would like to destructure this object {...obj} except label to get { test1: 'sth', test2: 'sth' }.
How to destructure the object without this key?
Should I create a new…
doobean
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9
votes
1 answer
Does Groovy have object destructuring like Javascript?
Does Groovy have object destructuring with multiple assignments like Javascript:
let options = {
title: "Menu",
width: 100,
height: 200
};
let {title, width, height} = options;
alert(title); // Menu
alert(width); // 100
alert(height); //…
dilvan
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9
votes
2 answers
Possible to destructure in JavaScript via bracket notation?
This is not necessarily an issue, more a curiosity that came up via an ESLint error which led me to wonder if there was a better way that just disabling ESLint for this line.
Consider the code snippet below. ESLint will give an error if the…
Ben
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