I would like to get the value from array under of object and also provide some error checking. I have following code to check if key exist and if value of key is array type or not. if yes, I would like to get the value from the key. it seems ok, but any better way I can get value? I tried to use const [value] = obj?.the_key but get exception Uncaught TypeError: undefined is not iterable (cannot read property Symbol(Symbol.iterator)) if
value from the_key is not array or the_key does not exist under object
const obj = {'theKey': ['correct value']}
const hasKey = obj['theKey'] !== undefined && Array.isArray(obj.theKey)
if (!hasKey) console.log('null')
const [value] = obj.theKey
console.log(value)
You can use the hasOwnProperty and isArray functions to check if your object has the key / property that you are looking for.
const obj = { 'theKey' : ['correct value'] };
let hasKey = obj.hasOwnProperty('theKey'); // This will return true / false
if (!hasKey) { // key does not exist
// error handling logic
}
Then you can check the data type of the value if it is array or not
if (hasKey) {
let keyVal = obj.theKey;
if (Array.isArray(keyVal)) { // returns true or false
// business logic with array
} else { // key value is not array
// error handling
}
}