Du kennst Destrukturierung erst

Für zukünftige Studenten des Kurses "React.js Developer" haben wir eine Übersetzung eines nützlichen Artikels vorbereitet.

Wir laden Sie außerdem ein, sich für eine offene Lektion zum Thema "Schreiben einer Anwendung in React + Redux" anzumelden.

, ES6 (destructuring assignment), - . , , , . . , .

.

const array = [1, 2, 3];
const obj = { x: 4, y: 5, z: 6 };

const a = array[0], b = array[1], c = array[2];
const x = obj.x, y = obj.y, z = obj.z

console.log(a, b, c); // 1 2 3
console.log(x, y, z); // 4 5 6

. ES6.

const array = [1, 2, 3];
const obj = { x: 4, y: 5, z: 6 };

const [ a, b, c ] = array;
const { x, y, z } = obj; 

console.log(a, b, c); // 1 2 3
console.log(x, y, z); // 4 5 6

. , .

const {x, y, z} = obj . const {x: x, y: y, z: z} = obj. , , . x: { x: x, .. }.

target = source target: source, source: target. :

const obj = { x: 4, y: 5, z: 6 };
const { x: X, y: Y, z: Z } = obj;

console.log(X, Y, Z); // 4, 5, 6

X, Y, Z obj.x, obj.y, obj.z . , , . JS- , .

, . , . , , . :

let a, b, c, x, y, z;

[a, b, c] = [1, 2, 3];
({x, y, z} = { x: 4, y: 5, z: 6 });

console.log(a, b, c, x, y, z); // 1 2 3 4 5 6

(), {..} LHS , .

. , . :

//  
const obj = {};
const computedProp = 'z';

[obj.a, obj.b, obj.c] = [1, 2, 3];
({ x: obj.x, y: obj.y, [computedProp]: obj[computedProp] } = { x: 4, y: 5, z: 6 });

console.log(obj.a, obj.b, obj.c); // 1 2 3
console.log(obj.x, obj.y, obj.z); // 4 5 6

//  
let array = [];

({ x: array[0], y: array[1], z: array[2]  } = { x: 4, y: 5, z: 6 });

console.log(array); // [4, 5, 6]

« ?» :

let x = 10, y = 20;

[y, x] = [x, y];

console.log(x, y); // 20 10

. :

const { a: X, a: Y } = { a: 1 };

console.log(X, Y); // 1 1

, ?️.

- /. , :

let a, b, c, x, y, z;

console.log({x, y, z } = { x: 4, y: 5, z: 6 }); // { x: 4, y: 5, z: 6 }
console.log([a, b, c] = [1, 2, 3]); // [1, 2, 3]

, :

let a, b, c, x, y, z;

[a, b] = [c] = [1, 2, 3];
( {x} = {y,z} = {x: 4, y: 5, z: 6} );

console.log(a, b, c); // 1 2 1
console.log(x, y, z); // 4 5 6

[a, b] = [c] = [1, 2, 3] & ( {x} = {y,z} = {x: 4, y: 5, z: 6} ) (.. [c] = [1, 2, 3] [a, b] , {y, z} = {x: 4, y: 5, z: 6} {x}).

, /. :

const [,,c] = [1, 2, 3];
const { y } = { x: 4, y: 5, z: 6 };

console.log(c, y); // 3 5 

, .

rest . :

const [a, ...b] = [1, 2, 3];
const { x, ...y } = { x: 4, y: 5, z: 6 };

console.log(a, b); // 1 [2, 3]
console.log(x, y); // 4 { y: 5, z: 6 }

Rest .

, . :

const { w = 7, x = 8, y, z } = { x: 4, y: 5, z: 6 };
const [ a = 9, b, c, d = 10 ] = [1, 2, 3];

console.log(w, x, y, z); // 7 4 5 6
console.log(a, b, c, d); // 1 2 3 10

/ . .

. :

const { w: WW = 10, x, y, z } = { x: 4, y: 5, z: 6 };

console.log(WW, x, y, z); // 10 4 5 6

, , , :

const array = [ 1, [2, 3, 4], 5 ];

const obj = { 
  x: {
    y: {
      z: 6
    }   
  }
}

const [ a, [ b, c, d ], e ] = array;

const { 
  x: { 
    y: { 
      z: w 
    } 
  } 
} = obj;

console.log(a, b, c, d, e); // 1 2 3 4 5
consoel.log(x); // {y: {z: 6}}
console.log(y) // {z: 6}
console.log(w); // 6

, . :

function baz([x, y]) {
  console.log(x, y);
}

baz([1, 2]); // 1 2
baz([1]); // 1 undefined
baz([, 2]); // undefined 2

"React.js Developer". " React+Redux" .