Question

I know that I can create an associative array like this:

var MyAssocArray = {'sky':'blue', 'grass':'green'};

And I am very fond of using this method.

What I would like to do and am having trouble with is this:

I have strings saved like this:

var MyString = "'sky':'blue', 'grass':'green'";

And I want to be able to do this now:

var MyAssocArray = {MyString};

When I try that – I get this error:

invalid object initializer

What am I doing wrong?
How can I achieve this?

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I found a different solution using PHP and JavaScript. The associative array string is echoed in the JavaScript code:

var Multidimensional_Arr[Multidimensional_Array_Key_Name] = {<?php echo $String_Pulled_From_Database; ?>}; // i.e. 'sky':'blue', 'grass':'green'

// The same can be done for a one-dimensional array
var My_Single_Dime_Arr = {<?php echo $String_Pulled_From_Database; ?>}; // i.e. 'sky':'blue', 'grass':'green'

Answer 1

Use JSON — it’s serialized JavaScript Object Notation and is pretty close to what you’re doing.

You’d need to do

var MyAssocArray = JSON.parse(MyString);

Also, JSON uses double quotes, not single quotes; if you use simple objects, you can probably write code to just replace ' with "" in your strings, but it’s tricky if the strings contain double-quotes.

If you are using a browser that doesn’t implement JSON.parse(), you can either use the implementation on the JSON website (see links at bottom of this page) or if you’re using jQuery, there’s jQuery.parseJSON().

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Warning: Your solution has a security risk, unless you are sure the data in the database has been sanitized:

 var My_Single_Dime_Arr = {<?php echo $String_Pulled_From_Database; ?>}

This is equivalent to a call to eval(); if your database string has any malicious code it can do bad things. This is one reason why JSON was invented — it’s easy to ensure that its contents are valid (and hence safe) before evaluated.

Your overall architecture, as you have presented it to us, is [data in database] -> server-side PHP -> client-side JavaScript. This is a classic example of serialized data. I realize you may have constraints to keep your system running without interruption, but a strict serialization format would make your system more secure.