Access an Object Key that Contains a Space in JavaScript

Access an Object Key that Contains a Space #

Use bracket notation to access a key that contains a space in an object, e.g. obj['my key']. The bracket [] notation syntax allows us to access an object's key, even if it contains spaces, hyphens or special characters.

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// ✅ Access key with space
const obj1 = {'first name': 'Tom'};
console.log(obj1['first name']); // 👉️ "Tom"

// ✅ Update key with space
obj1['first name'] = 'Alice';
console.log(obj1); // 👉️ {'first name': 'Alice'}

There are two ways to access properties in an object:

1. dot notation
2. bracket notation

A general rule of thumb followed by most developers is to use dot notation, unless the property in the object contains spaces, hyphens or starts with a number.

In all of the aforementioned scenarios, you have to use the bracket [] notation syntax.

Similarly to reading the value of a key that contains a space, we can use bracket notation to update the value.

You can also mix and match - use bracket notation where necessary and use dot notation in all other cases.

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const obj1 = {
  person: {
    'first name': 'Tom',
  },
};
console.log(obj1.person['first name']); // 👉️ "Tom"

obj1.person['first name'] = 'Alice';
// 👇️ {person:  {'first name': 'Alice'}}
console.log(obj1);

We can access the person property in the object using dot notation, because it contains no spaces.

However, the first name property does, so we have to use bracket notation.

The alternative is to be consistent and use bracket notation to access both of the keys.

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const obj1 = {
  person: {
    'first name': 'Tom',
  },
};
console.log(obj1['person']['first name']); // 👉️ "Tom"

obj1['person']['first name'] = 'Alice';
// 👇️ {person:  {'first name': 'Alice'}}
console.log(obj1);

Further Reading #

• Get the Last item in an Object using JavaScript
• Update an Object's Property in Array of Objects in JS