I passed the following object:
var myVar = { typeA: { option1: "one", option2: "two" } }
I want to be able to pull out the key typeA
from the above structure.
This value can change each time so next time it could be typeB
.
So I would like to know if there is a way for me to do something like the following pseudo code:
var theTypeIs = myVar.key();
This way when I can pass this object and I can pull out the first value of the object, in this case it is typeA
and then based on that I can do different things with option1
and option2
.
如果您确定对象中总是只有一个键,那么您可以使用Object.keys
:
theTypeIs = Object.keys(myVar)[0];
Like the other answers you can do theTypeIs = Object.keys(myVar)[0];
to get the first key. If you are expecting more keys, you can use
Object.keys(myVar).forEach(function(k) {
if(k === "typeA") {
// do stuff
}
else if (k === "typeB") {
// do more stuff
}
else {
// do something
}
});
If you want to get the key name of myVar
object then you can use Object.keys()
for this purpose.
var result = Object.keys(myVar);
alert(result[0]) // result[0] alerts typeA
I was searching to get a result for this either and I ended up with;
const MyObject = {
SubObject: {
'eu': [0, "asd", true, undefined],
'us': [0, "asd", false, null],
'aus': [0, "asd", false, 0]
}
};
For those who wanted the result as a string:
Object.keys(MyObject.SubObject).toString()
output: "eu,us,aus"
For those who wanted the result as an array:
Array.from(Object.keys(MyObject))
output: Array ["eu", "us", "aus"]
For those who are looking for a "contains" type method: as numeric result:
console.log(Object.keys(MyObject.SubObject).indexOf("k"));
output: -1
console.log(Object.keys(MyObject.SubObject).indexOf("eu"));
output: 0
console.log(Object.keys(MyObject.SubObject).indexOf("us"));
output: 3
as boolean result:
console.log(Object.keys(MyObject.SubObject).includes("eu"));
output: true
In your case;
var myVar = { typeA: { option1: "one", option2: "two" } } // Example 1 console.log(Object.keys(myVar.typeA).toString()); // Result: "option1, option2" // Example 2 console.log(Array.from(Object.keys(myVar.typeA))); // Result: Array ["option1", "option2" ] // Example 3 as numeric console.log((Object.keys(myVar.typeA).indexOf("option1")>=0)?'Exist!':'Does not exist!'); // Result: Exist! // Example 3 as boolean console.log(Object.keys(myVar.typeA).includes("option2")); // Result: True! // if you would like to know about SubObjects for(var key in myVar){ // do smt with SubObject console.log(key); // Result: typeA } // if you already know your "SubObject" for(var key in myVar.typeA){ // do smt with option1, option2 console.log(key); // Result: option1 // Result: option2 }
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