I want to check if a object value exist in a array of objects with "some".
I only can find that the object hobbys exist in the array with "some"
"users": [
{
"type": "User",
"name": "Sarah",
"hobbys":
{
first: "something1",
second: "something2"
}
}
]
users.some(item => item.hobbys); // true
I want to check if "first" value in "hobbys" exist.
Nikhil Aggarwal
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5 Answers 5
Check if the hobbys is an object and has an own property of first:
const users = [{
"type": "User",
"name": "Sarah",
"hobbys": {
first: "something1",
second: "something2"
}
}];
const userWithFirstHobbyExists = users.some(({ hobbys }) => (
typeof hobbys === 'object' && hobbys.hasOwnProperty('first')
));
console.log(userWithFirstHobbyExists);
answered May 10, 2019 at 9:08
CertainPerformance
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3 Comments
Yevhen Horbunkov
To me
hasOwnProperty() is a tool for tracking down the inheritance, which is muuuuch slower than simple users.some(item => item.hobbys.first != undefined || false). What's the benefit of using hasOwnProperty() here?CertainPerformance
hasOwnProperty is the way to check to see if the property exists on the object: != undefined will also evaluate to false if the property does exist, but its value is undefined. It's an edge case, but from OP's question, it's not clear if it's something to worry about or not. If he also wants to exclude first values of undefined, then you're right, check !== undefinedYevhen Horbunkov
The question body states "want to check if "first" value in "hobbys" exist", so regardless of the
first value, hasOwnProperty() seems to be massive overkill.You can try following assuming hobbys will always be an object and first will not have any falsy values.
let users = [{"type": "User","name": "Sarah","hobbys": {"first": "something1","second": "something2"}}];
console.log(users.some(item => item.hobbys && item.hobbys.first)); // true
answered May 10, 2019 at 9:12
Nikhil Aggarwal
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Comments
You can use "key" in obj also to check if a key is part if object.
const users = [{
"type": "User",
"name": "Sarah",
"hobbys": {
first: "something1",
second: "something2"
}
}];
const userWithFirstHobbyExists = users.some(({ hobbys }) => (
typeof hobbys === 'object' && ('first' in hobbys )
));
console.log(userWithFirstHobbyExists);Alternate and fast way to check is
const users = [{
"type": "User",
"name": "Sarah",
"hobbys": {
first: "something1",
second: "something2"
}
}];
const userWithFirstHobbyExists = users.some(({ hobbys }) => (
typeof hobbys === 'object' && hobbys['first'] !== undefined
));
console.log(userWithFirstHobbyExists);
answered May 10, 2019 at 9:11
Kaushik
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Comments
const users = [{
"type": "User",
"name": "Sarah",
"hobbys": {
first: "somethig1",
second: "something2"
}
}];
const hobbyExists = users.some(({ hobbys }) => (typeof hobbys === 'object' && hobbys['first']));
console.log(hobbyExists);
answered May 10, 2019 at 9:20
Manikandan Velayutham
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Comments
function will return true if it has value else false
let jData = {
"users": [{
"type": "User",
"name": "Sarah",
"hobbys": {
"first": "something1",
"second": "something2"
}
}]
};
function hasValue(data, obj, key) {
return data.some(item => item[obj] && item[obj][key]);
}
console.log(hasValue(jData.users, 'hobbys', 'second')) //true
console.log(hasValue(jData.users, 'hobbys', 'first')) // true
console.log(hasValue(jData.users, 'test', 'first')) //falseComments
lang-js
users.some(user => user.hobbies.first);user.hobbiesdoes not exist