It turns out not only tuples can be deconstructed but any type which has Deconstruct static (or extension) method with matching signature. Doing deconstruction correctly for IEnumerable is not trivial (see library suggested by David Arno in this answer), so let’s see how it works with simple IList instead (implementation is irrelevant, this one is … Read more
const data = { “key-with-dash”: [“BAZ”] } const {“key-with-dash”: foo} = data; console.log(“foo”, foo);
You could destructure with a renaming and take the same property for destructuring. const a = { b: { c: ‘Hi!’ } }; const { b: formerB, b: { c } } = a; console.log(formerB) console.log(c);
This is the proper syntax for destructuring an array inside an argument list: function f([a,b,c]: [number, number, number]) { }
The second example uses destructuring. This will call the specific variable (including functions) that are exported from the required module. For example (functions.js): module.exports = { func1, func2 } is included in your file: const { func1, func2 } = require(‘./functions’) Now you can call them individually, func1() func2() as opposed to: const Functions = … Read more
This is how it’s intended, as described in the documentation. /** * My cool function. * * @param {Object} obj – An object. * @param {string} obj.prop1 – Property 1. * @param {string} obj.prop2 – Property 2. */ const fn = function ({prop1, prop2}) { // Do something with prop1 and prop2 } So, your … Read more
Javascript 1.7 added destructuring assignment which allows you to do essentially what you are after. function getTuple(){ return [“Bob”, 24]; } var [a, b] = getTuple(); // a === “bob” , b === 24 are both true
What you’re looking at is a destructuring assignment. It’s a form of pattern matching like in Haskell. Using destructuring assignment you can extract values from objects and arrays and assign them to newly declared variables using the object and array literal syntax. This makes code much more succinct. For example: var ascii = { a: … Read more
The two pieces of code are equivalent but the first one is using the ES6 destructuring assignment to be shorter. Here is a quick example of how it works: const obj = { name: “Fred”, age: 42, id: 1 } //simple destructuring const { name } = obj; console.log(“name”, name); //assigning multiple variables at one … Read more
console.log(‘last’, [1, 3, 4, 5].slice(-1)); console.log(‘second_to_last’, [1, 3, 4, 5].slice(-2));