Function definePrivateGetters

definePrivateGetters<T, U extends Record<string, Func>>(
    target: T,
    props: U,
    configurable?: boolean,
): void

Defines hidden, non-configurable getters on an object.

Creates getter properties that are not enumerable and cannot be modified. Useful for computed properties and lazy-loaded values.

Type Parameters

T
U extends Record<string, Func>

Parameters

target: T
object to add getters to
props: U
getter functions to define
configurable: boolean = false
whether getters can be deleted or reconfigured

Returns void

Example

const user = { firstName: 'John', lastName: 'Doe' };

definePrivateGetters(user, {
    _fullName: () => `${user.firstName} ${user.lastName}`,
    _initials: () => `${user.firstName[0]}${user.lastName[0]}`
});

console.log(user._fullName); // 'John Doe'
console.log(Object.keys(user)); // ['firstName', 'lastName'] (getters hidden)

Example

class DataProcessor {
    constructor(data) {
        this.data = data;
        definePrivateGetters(this, {
            _size: () => this.data.length,
            _isEmpty: () => this.data.length === 0
        });
    }
}