@boost/decorators/mjs/Throttle.mjs

Experimental decorators for common patterns.

import { isMethod } from './helpers/isMethod.mjs';

/**
 * A method decorator that throttles the execution of a class method to
 * only fire once within every delay timeframe (in milliseconds).
 */
function Throttle(delay) {
  return (target, property, descriptor) => {
    if (process.env.NODE_ENV !== "production" && (!isMethod(target, property, descriptor) || !('value' in descriptor && typeof descriptor.value === 'function'))) {
      throw new TypeError(`\`@Throttle\` may only be applied to class methods.`);
    }

    // We must use a map as all class instances would share the
    // same boolean value otherwise.
    const throttling = new WeakMap();

    // Overwrite the value function with a new throttled function
    const func = descriptor.value;

    // @ts-expect-error Override generic
    descriptor.value = function throttle(...args) {
      if (throttling.get(this)) {
        return;
      }
      func.apply(this, args);
      throttling.set(this, true);
      setTimeout(() => {
        throttling.delete(this);
      }, delay);
    };
  };
}
export { Throttle };
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