Javascript 从数组创建对象
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Create object from array
提问by Hussain Dehgamwala
I want to create object from list of array. I have an array which is dynamic which suppose to be look like this:
我想从数组列表中创建对象。我有一个动态数组，它看起来像这样：
var dynamicArray = ["2007", "2008", "2009", "2010"];
var dynamicArray = ["2007", "2008", "2009", "2010"];
and with some javascript es6 I want to make an object like this:
并使用一些 javascript es6 我想制作一个这样的对象：
const obj = {
2007: {
x: width / 5,
y: height / 2
},
2008: {
x: (2 / 5) * width,
y: height / 2
},
2009: {
x: (3 / 5) * width,
y: height / 2
},
2010: {
x: (4 / 5) * width,
y: height / 2
}
}
don't worry about inner objects but just wanted to a make structure like this:
不要担心内部对象，而只是想制作这样的结构：
obj = {
2007: ...,
2008: ...,
...
}
Please help, Thanks.
请帮忙，谢谢。
回答by georg
Simply
简单地
const obj = {};
for (const key of yourArray) {
obj[key] = whatever;
}
or if you prefer "functional" style:
或者如果您更喜欢“功能性”风格：
const obj = yourArray.reduce((o, key) => Object.assign(o, {[key]: whatever}), {});
using the modern object spread operator:
使用现代对象扩展运算符：
const obj = yourArray.reduce((o, key) => ({ ...o, [key]: whatever}), {})
Example:
例子：
[
{ id: 10, color: "red" },
{ id: 20, color: "blue" },
{ id: 30, color: "green" }
].reduce((acc, cur) => ({ ...acc, [cur.color]: cur.id }), {})
Output:
输出：
{red: 10, blue: 20, green: 30}
Here is how it works:
下面是它的工作原理：
reduceis initialized with an empty object (empty {}at the end), therefore first iteration variables are acc = {}cur = { id: 10, color: "red" }. Function returns an object - this is why function body is wrapped in parentheses => ({ ... }). Spread operator doesn't do anything on the first iteration, so red: 10is set as first item.
reduce用一个空对象（{}最后为空）初始化，因此第一个迭代变量是acc = {}cur = { id: 10, color: "red" }。函数返回一个对象——这就是函数体被括在括号中的原因=> ({ ... })。Spread 运算符在第一次迭代时不做任何事情，因此red: 10设置为第一项。
On the second iteration variables are acc = { red: 10 }cur = { id: 20, color: "blue" }. Here the spread operator expandsaccand the function returns { red: 10, blue: 20 }.
在第二次迭代变量是acc = { red: 10 }cur = { id: 20, color: "blue" }。此处展开运算符展开acc并且函数返回{ red: 10, blue: 20 }。
Third iteration acc = { red: 10, blue: 20 }cur = { id: 30, color: "green" }, so when accis spread inside the object, our function returns the final value.
第三次迭代acc = { red: 10, blue: 20 }cur = { id: 30, color: "green" }，所以当acc在对象内部传播时，我们的函数返回最终值。
回答by Abderrahmane TAHRI JOUTI
The new Object.fromEntries, from ECMAScript 2019, makes it even easier to transform values from an array into keys in an object like follows
Object.fromEntries来自 ECMAScript 2019的 new使将数组中的值转换为对象中的键变得更加容易，如下所示
const dynamicArray = ["2007", "2008", "2009", "2010"];
const obj = Object.fromEntries(
dynamicArray.map(year => [year, {
something: "based",
on: year
}])
)
console.log(obj)回答by Ralexrdz
in js with es6 reduce function for array I do it like this
在 js 中使用 es6 减少数组函数我这样做
let x = [1,2,3]
let y = x.reduce((acc, elem) => {
acc[elem] = elem // or what ever object you want inside
return acc
}, {})
console.log(y) // {1:1, 2:2, 3:3}
回答by Alok Singh Mahor
var keys = ['key1', 'key2', 'key3']
var object = Object.assign({}, ...Object.entries({...keys}).map(([a,b]) => ({ [b]: 'someValue' })))
console.log(object)
This will produce
这将产生
{ key1: 'someValue', key2: 'someValue', key3: 'someValue' }
回答by jilykate
you can use:
您可以使用：
dynamicArray.map(value => ({'key': value, 'val': 'whatever you want'}));
