So, I have two classes
Item { name: string; desc: string; meta: string}
ViewItem { name: string; desc: string; hidden: boolean; }
I have an array of Item that needs to be converted into an array of ViewItem. Currently, I am looping through the array using for, instantiating ViewItem, assigning values to attributes and pushing it to the second array.
Is there a simple way to achieve this using lambda expressions? (similar to C#) Or is there any other means?
You haven't showed enough of your code, so I'm not sure how you instantiate your classes, but in any case you can use the array map function:
class Item {
name: string;
desc: string;
meta: string
}
class ViewItem {
name: string;
desc: string;
hidden: boolean;
constructor(item: Item) {
this.name = item.name;
this.desc = item.desc;
this.hidden = false;
}
}
let arr1: Item[];
let arr2 = arr1.map(item => new ViewItem(item));
This can be shorter with Object.assign:
constructor(item: Item) {
Object.assign(this, item);
}
you can do use something like this.
const newdata = olddata.map((x) => {
return { id: Number(x.id), label: x.label };
});
as the converted column will be mapped to the newdata array.
{ id: Number(...), label: ... } related to the required ViewItem class from the question? The two existing answers from 2016 and 2017 also use Array.map but actually answer the question because they actually return ViewItem instances.
newdata being the array of ViewItem. maybe the answer could have used SO's exact parameters naming.An alternate method is to use Object.keys,
class Item {
name: string;
desc: string;
meta: string
}
class ViewItem {
name: string;
desc: string;
hidden: boolean;
// additional properties
additionalProp: boolean;
constructor(item: Item) {
Object.keys(item).forEach((prop) => { this[prop] = item[prop]; });
// additional properties specific to this class
this.additionalProp = false;
}
}
Usage:
let arr1: Item[] = [
{
name: "John Doe",
desc: "blah",
meta: "blah blah"
}
];
let arr2: ViewItem[] = arr1.map(item => new ViewItem(item));
