Object methods in JavaScript with bracket notation

Question

var employee = {
  ["Last Name"]: "Smith",
  ["First Name"]: "Josh",
  ["Full Name"]: function() {
    return this["First Name"] + this["Last Name"]
  }
};
document.write("Good day" + this["Full Name"])

I'm currently learning JavaScript and I wanted to create an object with properties in two words using the bracket notation, unfortunately it gives me a result of Good dayundefined instead of Good day Josh Smith. I don't know what supposed to be the problem of my code...

You'll need to invoke the function to get the result you want. You're just writing the function itself, not it's return value. So change to document.write("Good day" + employee["Full Name"]()), note the extra set of parens at the end. — CRice
– CRice, Commented Mar 31, 2018 at 0:03

Barmar · Accepted Answer · 2018-03-31 00:05:56Z

5

Two problems.

You need to use employee["First Name"], not this["First Name"], since you're not inside an object method.
You need to call the function with ().

var employee = {
  ["Last Name"]: "Smith",
  ["First Name"]: "Josh",
  ["Full Name"]: function() {
    return this["First Name"] + this["Last Name"]
  }
};
document.write("Good day" + employee["Full Name"]())

answered Mar 31, 2018 at 0:05

Barmar

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1 Comment

Jake Go Over a year ago

Thank you so much! I'm currently learning JavaScript and your remarks with those problems are very helpful. Thank you.

Ori Drori · Accepted Answer · 2018-03-31 00:09:00Z

2

Convert "Full Name" to a getter, and refer to employee instead of this when you call it:

var employee = {
  "Last Name": "Smith",
  "First Name": "Josh",
  get "Full Name"() { // convert to getter
    return `${this["First Name"]} ${this["Last Name"]}`;
  }
};

document.write("Good day " + employee["Full Name"]) // refer to  employee instead of this

edited Mar 31, 2018 at 0:09

answered Mar 31, 2018 at 0:05

Ori Drori

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2 Comments

Abslen Char Over a year ago

Can you explain the reason behind wrapping this["Last Name"] and this["First Name"] inside the double bracket , knowing that it work fine without them ?

Ori Drori Over a year ago

You need to use the bracket notation to get the value. If you're talking about the curly brackets - this is an expression inside a template literal.

Javier S · Accepted Answer · 2018-03-31 00:06:59Z

1

var employee = { 
  "Last Name":"Smith", 
  "First Name":"Josh",
  "Full Name": function() {
    return  this["First Name"] +" "+ this["Last Name"];
  }
};
document.write("Good day " + employee["Full Name"]());

answered Mar 31, 2018 at 0:06

Javier S

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