Adding additional element to an existing JSON array - arrays

Question

I have a case like, I want to add elements into a JSON array in TypeScript like below
[
{
"a" : "a1",
"b" : "b1"
}
]
Now I want to add values to the above object without creating new block, for example, I want to add key, value pair as "C": "c1" and "d": "d1". After doing this, my JSON array must look like below
[
{
"a" : "a1",
"b" : "b1"
"c" : "c1",
"d" : "d1"
}
]
What I tried:
let someData : any [] = [];
someData.push({
"a" : "a1",
"b" : b1"
})
someData.push({
"c" : "c1",
"d" : d1"
})
But it is creating two records like below, but this is wrong
[
{
"a" : "a1",
"b" : "b1"
}
{
"c" : "c1",
"d" : "d1"
}
]
as well I tried using unshift as below
someData.unshift({
"c" : "c1",
"d" : d1"
})
this is returning result object as
[
{
"a" : "a1",
"b" : "b1"
}
{
"c" : "c1",
"d" : "d1"
}
]
Is there any way to do?
For example,
for(int i =0; i<3; i++){
someData.push({
i : i+1
})
But the above block of code is creating wrong array structure, but inturn I want as below
{
0 :1,
1:2,
2:3
}
}

Answer 1

Its supposed to be like this...
let someData : any [] = [];
someData.push({
"a" : "a1",
"b" : b1"
})
someData[0]["c"] = "c1";
someData[0]["d"] = "d1";
So when you log the values of someData ... it will show
console.log(someData); //[{"a":"a1","b" : "b1", "c":"c1", "d":"d1"}]
for looping through values...
let valuesToPut = [["c","c1"],["d","d1"]];
for(let i = 0; i < valuesToPut.length; i++){
someData[0][valuesToPut[i][0]] = valuesToPut[i][1]
}

Answer 2

is little confusion between Object and Array, here you try to add some item to the Object who are store on index 0 of your array.
let try following code :
let someData : any [] = [];
// Create first index of array and create on it your Object.
someData.push({
"a" : "a1",
"b" : b1"
});
// Override first index of array by merge of previous data + new one.
someData[0] = Object.assign(someData[0], {
"c1" : "c1",
"d1" : "d1"
});
Object assign documentation
Another way to do this: Object.defineProperties()

Answer 3

As you mensioned, it is an array json format.
So, if you access some element in the array, you should indicate the array index.
ex:
let tempArray = [
{
"a" : "a1",
"b" : "b1"
}
]
=>
tempArray[0] has this value.
{
"a" : "a1",
"b" : "b1"
}
So, if you add some additional values to the tempArray[0], you should access the element like below :
tempArray[0]['c'] = "c1";
tempArray[0]['d'] = "d1";

Answer 4

//Let's start with what you're doing
let someData = [];
someData.push({
"a" : "a1",
"b" : "b1"
});
// pushes a collection of 2 key value pairs in as the first entry to someData
someData.push({
"c" : "c1",
"d" : "d1"
});
// pushes a collection of 2 key value pairs in as the second entry to someData
console.log(someData);
// what you might want to do:
someData = [];
someData.push({
"a" : "a1",
"b" : "b1"
});
// pushes a collection of 2 key value pairs in as the first entry to someData
someData[0].c = "c1";
//Sets a value to the key c in the first element of some data
someData[0].d = "d1";
//Sets a value to the key d in the first element of some data
console.log(someData)
// What you probably want to do.
someData = {};
for(let i of [1,2,3,4]){
someData[String.fromCharCode(i+96)] = String.fromCharCode(i+96)+"1";
}
console.log(someData)