@exadel/esl/modules/esl-utils/decorators/bind.js

Exadel Smart Library (ESL) is the lightweight custom elements library that provide a set of super-flexible components

import { getPropertyDescriptor } from '../misc/object/utils';
/**
 * `@bind` decorator: lazily binds a class prototype method to its instance (`this`).
 * - Lazy one-time binding performed on first instance access
 * - Access via prototype returns the original (unbound) function
 * - Caches bound function on the instance (no further getter overhead)
 * - Only applicable to plain prototype methods (not accessors / fields)
 * - Reassignment installs the new function as a normal writable value (no rebinding logic)
 * - Preserves original enumerability; descriptor remains configurable
 *
 * @throws TypeError when applied to a non-method
 */
// eslint-disable-next-line @typescript-eslint/no-unsafe-function-type
export function bind(target, propertyKey, descriptor) {
    // Validation check
    if (!descriptor || (typeof descriptor.value !== 'function')) {
        throw new TypeError('Only class methods can be decorated via @bind');
    }
    // Original function
    const originalFn = descriptor.value;
    return descriptor = {
        enumerable: descriptor.enumerable,
        configurable: true,
        get: function getBound() {
            const proto = Object.getPrototypeOf(this);
            const desc = getPropertyDescriptor(proto, propertyKey);
            const isProtoCall = !desc || desc.get !== getBound;
            return isProtoCall ? originalFn : (this[propertyKey] = originalFn.bind(this));
        },
        set(value) {
            Object.defineProperty(this, propertyKey, {
                value,
                writable: true,
                configurable: true,
                enumerable: descriptor.enumerable
            });
        }
    };
}