I was working on a chart where i need my data to be sliced into small object based for better visibility. My array that i have is
{
"size":[
{
"timestamp":"1641329889000",
"size":12345,
"fees":123456,
"cost":168
},
{
"timestamp":"1641387032",
"size":456789,
"fees":4567891,
"cost":249
},
{
"timestamp":"1641435786",
"size":98765,
"fees":987654,
"cost":987
},
{
"timestamp":"1641435786",
"size":98765,
"fees":987654,
"cost":987
},
{
"timestamp":"1641435786",
"size":98765,
"fees":987654,
"cost":987
}
]
}
in which i want the array to be in this form
{
"size":{
"timestamp": ["1641329889000","1641387032","1641435786"],
"size": [12345,456789,98765],
"fees": [123456,4567891,987654],
"cost": [168,249,987]
}
}
i can achieve this using foreach and push like this
result.forEach(element => {
this.state.timestamp.push(element.timestamp);
this.state.size.push(element.size);
});
But i want this array to have the items only from the 10,20,30,40th index alone I want not all the value. the values should be chosen only in the basis of x+10 Could anyone help me on this
You could take a for loop and a step for incrementing the index.
const
step = 10,
keys = ["timestamp", "size", "fees", "cost"],
result = Object.fromEntries(keys.map(k => [k, []]));
for (let i = 0; i < size.lenght; i += step) {
keys.forEach(key => result[key].push(size[i][key]));
}
Using forEach is a waste of resources.
You can use for instead:
for(let i=0;i<result.length;i+10){
this.state.timestamp.push(result[i].timestamp);
this.state.size.push(result[i].size);
}
For setting the state you should use setState not just push to it.
let tmp = {
...this.state
}
for(let i=0;i<result.length;i+10){
tmp.size.timestamp.push(result[i].timestamp);
tmp.size.push(result[i].size);
}
this.setState(tmp)
Instead of forEach why not just use a for loop, and on the condition use the modulus % operator with 10? Like if (i % 10 == 0) inside of the for loop, or just increment i by 10 like i+=10.