使用类似结构的语法在对象中分配多个值

Question

Is there a cleaner way of setting the values a , b , and c in bar . Something similar to ES6 destructuring-assignment syntax?

bar = { foo: 10, a: 0, b: 0, c: 0, baz: 14 };

myFunc = (myObj) => {
    const { foo } = myObj;
    let a, b, c;
    a = 1 + foo;
    b = 2 + foo;
    c = 3 + foo;
    myObj.a = a;
    myObj.b = b;
    myObj.c = c;
}

myFunc(bar);

Assuming that bar has already been instantiated somewhere else, I'd like to set the new values without creating/assigning a new object to bar . We could do something like this myObj = {...myObj, a, b, c} , but that'd assign a new object to bar , from my understanding.

Answer 1

Based on this answer to a similar question , you can use Object.assign() .

bar = { foo: 10, a: 0, b: 0, c: 0, baz: 14 };

myFunc = (myObj) => {
    const { foo } = myObj;
    let a, b, c;
    a = 1 + foo;
    b = 2 + foo;
    c = 3 + foo;
    Object.assign(myObj, {a: a, b: b, c: c});
}

myFunc(bar);

or of course

    const { foo } = myObj;
    Object.assign(myObj, {a: 1 + foo, b: 2 + foo, c: 3 + foo})

Answer 2

ES6 did not bring in any features that would make this code simpler. There is one feature available, but it is a best practice not to use it. The with keyword

with (bar) {
 a = foo+1
 b = foo+2
 c = foo+3
}

The best way to make that code shorter would be to wrap the logic into a method call if it is being re-used a lot.

Answer 3

You can use an object literal shorthand and construct your object the other way round:

const foo = 10;
const a = 1+foo, b = 2+foo, c = 3+foo;
const bar = { foo, a, b, c };

which of course could be shortened to simply

const bar = { foo, a: 1+foo, b: 2+foo, c: 3+foo };