Targeting an array of objects in JavaScript

Question

I have a value in this format:

var state = [{"industry-type":"football","your-role":"coach"}]

I would like to output "football". How can I do this?

I've tried state[0].industry-type but it returns an error:

Uncaught ReferenceError: type is not defined

Any help appreciated.

What you have is an array of object(s), not JSON. – Felix Kling Mar 17 '17 at 15:57 — Felix Kling, Mar 17 '17 at 15:57

score 2 · Answer 1 · edited Mar 17 '17 at 15:49

2

It does not like the '-' in your property name, try:

state[0]['industry-type']

edited Mar 17 '17 at 15:49

Pranav C Balan

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answered Mar 17 '17 at 15:49

paul

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score 1 · Answer 2 · answered Mar 17 '17 at 15:49

1

This happens because you can't access a property with - directly.

var state = [{"industry-type":"football","your-role":"coach"}];

console.log(state[0]['industry-type']);

answered Mar 17 '17 at 15:49

Erazihel

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score 1 · Answer 3 · answered Mar 17 '17 at 15:50

The - symbol is reserved in Javascript, you cannot use it to refer to an object's property because Javascript thinks you're trying to do subtraction: state[0].industry - type; Hence the error "Uncaught ReferenceError: type is not defined" - it is looking for a variable named type to subtract with, which it can't find.

Instead, refer to it by:

state[0]['industry-type']

Because in Javascript, object.property and object['property'] are equal.

For what it's worth, if you have control over those names, it is best practice in Javascript to name things with Camel Case, so your variable would be defined as:

var state = [{"industryType":"football","yourRole":"coach"}]

Then, you could access it like:

state[0].industryType

score 1 · Answer 4 · edited May 23 '17 at 11:46

In order to be able to use dot notation then your:

...property must be a valid JavaScript identifier, i.e. a sequence of alphanumerical characters, also including the underscore ("_") and dollar sign ("$"), that cannot start with a number.

From MDN

Like the other answers pointed out, you have to use square bracket notation to access property names of an object that are not valid JavaScript identifiers.

e.g.

state[0]["industry-type"]

Targeting an array of objects in JavaScript

5 Answers5