带有对象的粗箭头

Question

Is there a way to use a fat arrow with an object?

The following code prints out the contents of the array "test" in the console.

//With array
let test = [1, 2, 3, 4];
test.forEach(number => console.log(number));

I'm looking for a way to have the same output but with "test" being an object, not an array (like below). is there a (relatively) simple way of doing this?

//With object
let test = {
  a: 1,
  b: 2,
  c: 3,
  d: 4
}
test.forEach(number => console.log(number));

Answer 1

There is a couple of ways to do this:

Object.keys(test).forEach(key => console.log(test[key]));

Object.keys is the oldest method, available since ES5.

However, as you're using ES6 method you can probably use newer methods:

Object.keys(test) // ['a', 'b', 'c', 'd']
Object.values(test) // [1, 2, 3, 4]
Object.entries(test) // [['a', 1], ['b', 2], ['c', 3], ['d', 4]]

Answer 2

Array methods cannot be used on an object. Use Object.keys to get an array of object's keys, then use array method forEach

 let test = { a: 1, b: 2, c: 3, d: 4 } Object.keys(test).forEach(number => console.log(test[number])); 

Answer 3

for array you can use array.forEach() and for object you need to use Object.values(object).forEach() for values and Object.keys(object).forEach() for object keys. :D

 //With array var test = [1, 2, 3, 4]; console.log("Array"); test.forEach(number => console.log(number)); console.log("Obejct"); //With object var testObj = { a: 1, b: 2, c: 3, d: 4 } Object.values(testObj).forEach(number => console.log(number)); 

Answer 4

You have following options

1) Object.keys()

test = {
  a: 1,
  b: 2,
  c: 3,
  d: 4
}

Object.keys(test).forEach(key => console.log(test[key]))

Object.keys returns an array of keys of the object it was called on.

2) Object.values()

test = {
   a: 1,
   b: 2,
   c: 3,
   d: 4
}

Object.values(test).forEach(value=> console.log(value))

Object.values Returns an array whose elements are the enumerable property values found on the object.

Answer 5

Or you can use Object.values()

let test = {
  a: 1,
  b: 2,
  c: 3,
  d: 4
}
Object.values(test).forEach(number => console.log(number));