How to form a new object from a json as key value pair in Typescript? - json

Question

I have a below json array of objects which have data of currency list.
[
{
id:"AUD",
value:"1.55"
},
{
id:"BGN",
value:"1.95"
},
{
id:"USD",
value:"1.17"
},
{
id:"CAD",
value:"1.51"
},
{
id:"EUR",
value:"1"
},
{
id:"INR",
value:"80.00"
}
]
I want to form a new array of object say newList with only currency value for USD, CAD and EUR. I can manually find the position of the object(eg: say item[3].value will give rate for CAD)and update the new object but I want to look for key values and get the values instead of getting index positions manually. How to do the same?

Answer 1

I hope this is what you expect.
This is your original list.
const list = [{ id: "AUD", value: "1.55" }, { id: "BGN", value: "1.95" }, { id: "USD", value: "1.17" }, { id: "CAD", value: "1.51" }, { id: "EUR", value: "1" }, { id: "INR", value: "80.00" }];
And this is how you can extract the wanted objects by comparison with their id.
const newList = list.filter(el => this.matches(el.id));
console.log(newList);
This method does the comparison for you and returns true when id matches. You can dynamically remove or add currencies.
private matches(id: string): boolean {
let match: boolean = false;
switch (id) {
case 'AUD':
match = true;
break;
case 'USD':
match = true;
break;
case 'EUR':
match = true;
break;
default:
match = false;
break;
}
return match;
}