How to use join() on an object that looks like an array?-CodePudding

I have an object that contains key pair values of objects that are in array form:

let obj = {};
let joinedData;

obj["key1"] = ["val1", "val2"];
obj["key2"] = ["val3", "val4"];

I want to join all the values together as a string:

for (const [key, values] of Object.entries(obj)) {
    joinedData = `${values.join(",")}`;
}

The expected result is "val1,val2,val3,val4"

But joinedData is empty.

I suspect that it's because the values are objects and not array (when I use typeof).

How to get the expected result in this case?

CodePudding user response：

You can use Object.values and flat:

let obj = { key1: ["val1", "val2"], key2: ["val3", "val4"] };
let joinedData = Object.values(obj).flat().join();

console.log(joinedData);

If you have some arrays that contain empty strings, then you may want to filter those out, with filter(Boolean):

let obj = { key1: ["val1", "val2"], key2: ["val3", "val4"], key3: [""], key4: [""] };
let joinedData = Object.values(obj).flat().filter(Boolean).join();

console.log(joinedData);

CodePudding user response：

You can use this - joinedData = Object.values(obj).flat().join(',')

CodePudding user response：

First join the both list in any single list like

var newlist = obj["key1"].join(obj["key2"]);

After join the values by comma seprated

joinedData = newlist.join(',');

CodePudding user response：

get all values from obj using let objValues = Object.values(obj);

now you can a for loop over obj values and append both elms like for(const v of objValues) { joinedData.push(v[0]); joinedData.push(v[1]); } or nested for loop works too

let obj = {};
let joinedData = [];

obj["key1"] = ["val1", "val2"];
obj["key2"] = ["val3", "val4"];

let objValues = Object.values(obj); //List of tuples ?

for (const v of objValues) {
  joinedData  = v[0]   ',';
  joinedData  = v[1]   ' ';
}

console.log(joinedData)

CodePudding user response：

if you were to write out your object literally, you would have:

 obj = {key1 : ["val1", "val2"], key2 : ["val3", "val4"]}

Array.join() concatenates array elements into a string. Array elements that are arrays themselves cannot be directly concatenated into a string. Try:

let str = '';
for(let i of Object.values(obj)) {  // retrieve each value (which is an array)
    str  = i.join(', ')   ', ';    //  join elements of each array & concatenate
}                                  //   extra comma between each joined array
console.log(str)

You still need to strip the extra comma off the end