[英]Get the key of a JS Object from the value
I am trying to get the key
of a JS Object
in Typescript from an input value, the problem is that the values are inside an Array
.我试图从输入值中获取 Typescript 中
JS Object
的key
,问题是这些值在Array
内。
This is what I have seen in the case that the value is not in an array:这是我在值不在数组中的情况下看到的:
const exampleObject = {
key1: 'Geeks',
key2: 'Javascript'
};
function getKeyByValue(object, value) {
for (var prop in object) {
if (object.hasOwnProperty(prop)) {
if (object[prop] === value)
return prop;
}
}
}
console.log(getKeyByValue(exampleObject,'Geeks')) // key1
This is an example of my object that I want to get the key from:这是我想从中获取密钥的对象的示例:
const exampleObject = {
key1: ['Geeks','test1','test2'],
key2: ['Javascript','test3','test4']
};
function getKeyByValue(object, value) {
for (var prop in object) {
if (object.hasOwnProperty(prop)) {
if (object[prop] === value)
return prop;
}
}
}
console.log(getKeyByValue(exampleObject,'Geeks')) // undefined
I need to get the key without using Array.prototype.includes()
, because typing the resulting variable as String
gives me an error
that it may be undefined.我需要在不使用
Array.prototype.includes()
的情况下获取密钥,因为将结果变量键入为String
会给我一个error
,即它可能未定义。
My problem : I don't know how to go through the array inside the function to find the value and get the key我的问题:我不知道如何通过函数内部的数组来查找值并获取密钥
Update :更新:
What I want is to avoid the possibility of returning an undefined, since the input value will always be inside the object, how can I achieve this?我想要的是避免返回未定义的可能性,因为输入值将始终在对象内部,我该如何实现呢?
@segmet You can use my code @segmet 你可以使用我的代码
const exampleObject = {
key1: ['Geeks', 'test1', 'test2'],
key2: ['Javascript', 'test3', 'test4']
};
function getKeyByValue(object, value) {
var output = "";
for (var prop in object) {
// finding and removing element from array
object[prop].find(i => {
if (i === value) {
output = prop;
return prop;
}
}
)
}
return output
}
console.log(getKeyByValue(exampleObject, 'Geeks'))
function getKeyByValue(object, value) {
const key = Object.entries(object).filter(([key, val]) => val.includes(value));
return Object.fromEntries(key);
}
Try this function instead You will get the object matching your keys试试这个功能你会得到匹配你的钥匙的对象
You can do something like this and then check for null
你可以做这样的事情,然后检查
null
const getKeyFromValue = (obj:Object, value:string | string[]) => {
for (let key in obj) {
if (typeof value === 'string') {
if (obj[ key ].includes(value)) {
return key;
}
}
else if (Array.isArray(value)) {
if (obj[ key ].every(val => value.includes(val))) {
return key;
}
}
}
return null;
}
One more try:再试一次:
const exampleObject = { key1: ['Geeks','test1','test2'], key2: ['Javascript','test3','test4'] }; function getKeyByValue(obj, data) { for (const [key, value] of Object.entries(obj)) { return (~value.indexOf(data)) ? key : false } } console.log(getKeyByValue(exampleObject,'Geeks'))
You can achieve this with a single line of code by using 3 JavaScript methods - Object.keys() , Array.find() & Array.indexOf() :您可以通过使用 3 个 JavaScript 方法 - Object.keys() 、 Array.find()和Array.indexOf() ,通过一行代码来实现这一点:
const exampleObject = { key1: ['Geeks','test1','test2'], key2: ['Javascript','test3','test4'] }; function getKeyByValue(object, value) { const res = Object.keys(exampleObject).find(key => exampleObject[key].indexOf(value) !== -1); return res || '' } console.log(getKeyByValue(exampleObject,'Geeks'))
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