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How to access an object property with a dynamically-computed name in JavaScript
source link: https://typeofnan.dev/access-dynamic-property-javascript/
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How to access an object property with a dynamically-computed name in JavaScript
Nick Scialli
March 18, 2023
Using a dynamic object key name is critical for creating dynamic JavaScript applications. Let’s consider the following object that represents a person:
const person = {
name: 'Wilma',
age: 27,
};
Dot notation doesn’t work
If we know what key we need to access, we can simply use dot notation to get it. For example, we can console.log
ther person’s name:
console.log(person.name);
// Wilma
But what if we have a variable that represents the key we want? In our example, that variable can be either "name"
or age:
const person = {
name: 'Wilma',
age: 27,
};
const key = 'age';
We can’t use dot notation in this instance. Trying to get person.key
will fail because JavaScript will look for a key
property on person
, which doesn’t exist.
Bracket notation works!
Fortunately, we can use bracket notation in this case: person[key]
const person = {
name: 'Wilma',
age: 27,
};
const key = 'age';
console.log(person[key]);
// 27
And there you have it! You can now use a dynamic key to access a property on a JavaScript object.
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