Question

I want to create a JSON string from a javascript for loop. This is what I tried to do (which gives me something that looks like a JSON string), but it does not work.

var edited = "";
for(var i=1;i<POST.length-1;i++) {
    edited += '"'+POST[i].name+'":"'+POST[i].value+'",';
}

It gives me this:

"type":"empty","name":"email-address","realname":"Email Address","status":"empty","min":"empty","max":"empty","dependson":"empty",

This does not work if I try to convert it into a JSON object later.

Answer 1

Two problems:

• You want an object, so the JSON string has to start with { and end with }.
• There is a trailing , which may be recognized as invalid.

It’s probably better to use a library, but to correct your code:

• Change var edited = ""; to var edited = "{"; to start your JSON string with a {
• Add edited = edited.slice(0, -1); after the for loop to remove the trailing comma.
• Add edited += "}"; after the previous statement to end your JSON string with a }

Your final code would be:

var edited = "{";
for(var i=1;i<POST.length-1;i++) {
    edited += '"'+POST[i].name+'":"'+POST[i].value+'",';
}
edited = edited.slice(0, -1);
edited += "}";

Again, it’s best to use a library (e.g. JSON.stringify) by making an object with a for loop, adding properties by using POST[i].name as a key and POST[i].value as the value, then using the library to convert the object to JSON.

Also, you are starting with index 1 and ending with index POST.length-2, therefore excluding indices 0 (the first value) and POST.length-1 (the last value). Is that what you really want?