CODEWITHSUNDEEP
javascriptnode.jsmongodbserverclient
The_Babu
The_Babu

Reputation: 342

"Evaluate" Function that is stored in MongoDB Server

My collection looks like this:

> db.projects_columns.find()
{ "_id" : "5b28866a13311e44a82e4b8d", "checkbox" : true }
{ "_id" : "5b28866a13311e44a82e4b8e", "field" : "_id", "title" : "ID", "sortable" : true }
{ "_id" : "5b28866a13311e44a82e4b8f", "field" : "Project", "title" : "Project", "editable" : { "title" : "Project", "placeholder" : "Project" } }
{ "_id" : "5b28866a13311e44a82e4b90", "field" : "Owner", "title" : "Owner", "editable" : { "title" : "Owner", "placeholder" : "Owner" } }
{ "_id" : "5b28866a13311e44a82e4b91", "field" : "Name #1", "title" : "Name #1", "editable" : { "title" : "Name #1", "placeholder" : "Name #1" } }
{ "_id" : "5b28866a13311e44a82e4b92", "field" : "Name #2", "title" : "Name #2", "editable" : { "title" : "Name #2", "placeholder" : "Name #2" } }
{ "_id" : "5b28866a13311e44a82e4b93", "field" : "Status", "title" : "Status", "editable" : { "title" : "Status", "type" : "select", "source" : [ { "value" : "", "text" : "Not Selected" }, { "value" : "Not Started", "text" : "Not Started" }, { "value" : "WIP", "text" : "WIP" }, { "value" : "Completed", "text" : "Completed" } ], "display" : "function (value, sourceData) { var colors     = { 0: 'Gray', 1: '#E67C73', 2: '#F6B86B', 3: '#57BB8A' }; var status_ele = $.grep(sourceData, function(ele){ return ele.value == value; });  $(this).text(status_ele[0].text).css('color', colors[value]); }", "showbuttons" : false } }

You can see that in the very last document that I have stored a function as text.Now the idea is that I will request this data and will be in an Javascript Array format.

But I want to be able to have my function without the quotes! You can see that simply evaluating it will not work because I need to have it still needs to be inside of the object ready to be executed when the array is used.

How can I achieve this?

Thanks for any help!

Upvotes: 0

Views: 91

Answers (1)

Keveloper
Keveloper

Reputation: 783

There are two possible solutions, but neither particularly safe and you should strongly consider why you need to store functions as strings in the first place. That being said, you could do two things.

The simplest is to use eval. To do so, you would have to first parse the object like normal, and then set the property that you want to the result of eval-ing the function string, like so:

// Pass in whatever JSON you want to parse
var myObject = JSON.parse(myJSONString);
// Converts the string to a function
myObject.display = eval("(" + myObject.display + ")");
// Call the function with whatever parameters you want
myObject.display(param1, param2);

The additional parentheses are to make sure that evaluation works correctly. Note, that this is not considered safe by Mozilla and there is an explicit recommendation not to use eval.

The second option is to use the Function constructor. To do so, you would need to restructure your data so that you store the parameters separately, so you could do something like this:

var myObject = JSON.parse(myJSONString);
// displayParam1 and displayParam2 are the stored names of your parameters for the function
myObject.display = Function(myObject.displayParam1, myObject.displayParam2, myObject.display)

This method definitely takes more modification, so if you want to use your existing structure, I recommend eval. However, again, make sure that this is absolutely necessary because both are considered unsafe since outside actors could basically inject code into your server.

Upvotes: 1

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