Getting a value from a named key in javascript object

Question

I am attempting to get a specific value by supplying the literal key in a javascript object. In the image below you see that "filter" is equal to "Approved". This is coming from reimb_status_description in the image below.

Line 6 of the code is where I assign filter to the value.

const filter = Object.values(jsonData[i]["reimb_status_description"]).join("");

What I do not understand is that if I did not end with .join(""), filter would read as "A,p,p,r,o,v,e,d" which is apparently an array of the letters. Could someone please help me understand why the result is an array instead of just a string? Also, is there a better method of extracting the data I am looking for?

function PopulateReimbursementTable(jsonData, appliedFilter)
{
    ClearReimbursementTable();

    for(var i = 0; i < jsonData.length; i++)
    {
        const tr = document.createElement("tr");
        const entries = Object.entries(jsonData[i])

        const filter = Object.values(jsonData[i]["reimb_status_description"]).join("");
        console.log("filter: " + filter)
        for(const [key, property] of entries)
        {
            if(fields.includes(key)){
                console.log(key + "\t" + property);
                const td = document.createElement("td");
                if(key == "reimb_date_submitted" || key == "reimb_date_resolved"){
                    if(property == null)
                    {
                        td.innerHTML = "tbd";
                    }else{
                        var d = new Date(property);
                        let formatted_date = appendLeadingZeroes((d.getMonth() + 1)) + "-" + appendLeadingZeroes(d.getDate()) + "-" + d.getFullYear();
                        //console.log(formatted_date)
                        td.innerHTML = formatted_date;
                    }
                } else if(key == 'reimb_amount'){
                    if(property === null || property === undefined)
                    {
                        td.innerHTML = "tbd";
                    }else{
                        td.innerHTML = formatter.format(property);
                    }   
                }
                else
                {
                    if(property === null || property === undefined)
                    {
                        td.innerHTML = "tbd";
                    }else{
                        td.innerHTML = property;
                    }               
                }

                if(fields.includes(key))
                {
                    tr.appendChild(td);
                }
            }

        }

        if(appliedFilter == "All"){
            reimbTableBody.appendChild(tr);
        }
        else if(filter == appliedFilter){
            reimbTableBody.appendChild(tr);
        }
    }
}

`jsonData[i]["reimb_status_description"]` is a *string*, so if you do `Object.values` on it, it would be treated as an array and thus you get the values of said array. — VLAZ, Apr 03 '20 at 05:47
I'd suggest to learn about filter, map and reduce funtions, they're very helpful. I like this post https://medium.com/poka-techblog/simplify-your-javascript-use-map-reduce-and-filter-bd02c593cc2d — z44.nelther, Apr 03 '20 at 05:55

KooiInc · Accepted Answer · 2020-04-03T05:57:54.760

2

That is what Object.values does with a String¹. So in your case I think you can use jsonData[i].reimb_status_description to retrieve the string value.

¹ Why? Because a string is actually a one-dimensional array with elements of the type character.

console.log(Object.values("some string"));

// this would deliver the string though
console.log(Object.values({someString: "some string"})[0]);

.as-console-wrapper { top: 0; max-height: 100% !important; }

edited Apr 03 '20 at 05:57

answered Apr 03 '20 at 05:50

KooiInc

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Yes, I just updated the code with that and it is giving the results I was looking for. I was too focused on the whole Object.entries(jsonData[i]) that I failed to realize that jsonData[i] is in JSON notation. – Dave Hock Apr 03 '20 at 05:59

score 1 · Answer 2 · answered Apr 03 '20 at 06:00

According to MDN doc:

The Object.values() method returns an array of a given object's own enumerable property values

It seems that jsonData[i]["reimb_status_description"] returns string. Any values passed to Object.values is converted to object. String primitive type can be converted to String array-like object (here more details) in javascript. So when you pass string to Object.values it's converted to array-like object which values are individual characters. So in such case Object.values returns an array with individual characters of given string.

Getting a value from a named key in javascript object

2 Answers2