Remove data array JS

Question

I am working on creating a file where data can be read from a JSON file.

I can add new names to the file but I am unable to delete. When I enter a name to delete it actually adds the name to the file.

Why is it adding & not deleting? The objective is to be able to delete a specific name from the list that will be generated.

Thank you in advance! Here is my code with comments on what I am attempting to do.

// POST request to add to JSON & XML files
router.post('/post/json', function(req, res) {

    // Function to read in a JSON file, add to it & convert to XML
    function appendJSON(obj) {

        // Read in a JSON file
        var JSONfile = fs.readFileSync('Staff.json', 'utf8');

        // Parse the JSON file in order to be able to edit it 
        var JSONparsed = JSON.parse(JSONfile);

        // Add a new record into country array within the JSON file    
        JSONparsed.member.push(obj);

        // Beautify the resulting JSON file
        var JSONformated = JSON.stringify(JSONparsed, null, 4);

        // Delte a specific entry from JSON file
        var i = member.indexOf(" ");
        if (i != -1) {
            member.splice(i,1);
        }

        // Write the updated JSON file back to the system 
        fs.writeFileSync('Staff.json', JSONformated);

        // Convert the updated JSON file to XML     
        var XMLformated = js2xmlparser.parse('staff', JSON.parse(JSONformated));

        // Write the resulting XML back to the system
        fs.writeFileSync('Staff.xml', XMLformated);
    }

    // Call appendJSON function and pass in body of the current POST request
    appendJSON(req.body);

    // Re-direct the browser back to the page, where the POST request came from
    res.redirect('back');
});

Here is an example of the JSON file

{ 
    "member": [ 
        { 
            "Full_Name": "", 
            "Address": "", 
            "Gender": "",     
            "Phone_Number": "" 
        }
    ]
}

NtFreX · Accepted Answer · 2016-12-04 16:30:09Z

1

The splice function removes the item from the array and returns the deleted item. So if you want to delete an item by an attribute from your JSON like Full_Name you have to find the index of the item first.

var nameToSearch = "MyName";
var itemIndex = -1;
for(var i = 0; i < JSONparsed.member.length; i++) {
    if(JSONparsed.member[i].Full_Name === nameToSearch) {
        itemIndex = i;
    }
}

And then you can delete the item like you did.

if (itemIndex != -1) {
    JSONparsed.member.splice(itemIndex,1);
}

The problem you most likely had was that the itemIndex was allways -1 as indexOf did not know which attribute to check and just checks for the whole object.

Also the following lines have to be after the code above. (So after any changes you make to the json)

// Beautify the resulting JSON file
var JSONformated = JSON.stringify(JSONparsed, null, 4);

I also recomend reading this turtorial about javascript debugging. It makes your live a lot easyier to find mistakes.

edited Dec 4, 2016 at 16:30

answered Dec 4, 2016 at 15:12

NtFreX

11.6k3 gold badges47 silver badges68 bronze badges

Sign up to request clarification or add additional context in comments.

12 Comments

ThisisD Over a year ago

Am I better to use the above or use a delete method here?

Davin Tryon Over a year ago

my bad, I always get splice and slice confused. Turns out splice does modify in place :)

baao Over a year ago

The splice method returns "An array containing the deleted elements." developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/…

NtFreX Over a year ago

@baao ups my mistake. I changed my answer

ThisisD Over a year ago

@Dr.Fre Thanks guys but for some reason it is still adding the information onto the end of the file instead of deleting it. Can't figure out what I am doing wrong here

|

Collectives™ on Stack Overflow

Remove data array JS

1 Answer 1

12 Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

12 Comments

Your Answer

Sign up or log in

Post as a guest

Related