Javascript 如何使用lodash过滤对象的键？
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How to filter keys of an object with lodash?
提问by Freewind
I have an object with some keys, and I want to only keep some of the keys with their value?
我有一个带有一些键的对象，我只想保留其中一些键的值？
I tried with filter:
我试过filter：
const data = {
aaa: 111,
abb: 222,
bbb: 333
};
const result = _.filter(data, (value, key) => key.startsWith("a"));
console.log(result);<script src="https://cdnjs.cloudflare.com/ajax/libs/lodash.js/4.17.15/lodash.min.js"></script>But it prints an array:
但它打印了一个数组：
[111, 222]
[111, 222]
Which is not what I want.
这不是我想要的。
How to do it with lodash? Or something else if lodash is not working?
如何用 lodash 做到这一点？如果 lodash 不起作用，或者其他什么？
回答by serg10
Lodash has a _.pickByfunctionwhich does exactly what you're looking for.
Lodash 有一个_.pickBy函数，它完全符合你的要求。
var thing = {
"a": 123,
"b": 456,
"abc": 6789
};
var result = _.pickBy(thing, function(value, key) {
return _.startsWith(key, "a");
});
console.log(result.abc) // 6789
console.log(result.b) // undefined<script src="https://cdn.jsdelivr.net/lodash/4.16.4/lodash.min.js"></script>回答by Krystian Jankowski
回答by PaulMest
Here is an example using lodash4.x:
下面是一个使用lodash4.x的例子：
const data = {
aaa: 111,
abb: 222,
bbb: 333
};
const result = _.pickBy(data, (value, key) => key.startsWith("a"));
console.log(result);
// Object { aaa: 111, abb: 222 }<script src="https://cdnjs.cloudflare.com/ajax/libs/lodash.js/4.17.15/lodash.min.js"></script>
<strong>Open your javascript console to see the output.</strong>回答by thomax
A non-lodash way to solve this in a fairly readable and efficient manner:
一种以相当可读和有效的方式解决这个问题的非 lodash 方法：
function filterByKeys(obj, keys = []) {
const filtered = {}
keys.forEach(key => {
if (obj.hasOwnProperty(key)) {
filtered[key] = obj[key]
}
})
return filtered
}
const myObject = {
a: 1,
b: 'bananas',
d: null
}
const result = filterByKeys(myObject, ['a', 'd', 'e']) // {a: 1, d: null}
console.log(result)