Debounce decorator Angular

Debounce_decorator.js

/**
 * Debounce a method
 */
function debounce(ms) {
  return function(target: any, key: any, descriptor: any) {
    const oldFunc = descriptor.value
    const newFunc = _debounce(oldFunc,ms)
    descriptor.value = function() {
        return newFunc.apply(this,arguments)
    }
  }
}

function _debounce(fn, ms) {
    _debounce.inProgress === undefined ? _debounce.inProgress = false : null
    if (!_debounce.inProgress) {
        _debounce.inProgress = true
        fn.apply()
        const timeout = setTimeout(() => {
            _debounce.inProgress = false
            clearTimeout(timeout)
        }, ms)
    }
}

...

@Component({
  selector: 'app-root',
  template: `
    <div>
        <input (change)="changeFn" placeholder="Search words here..." />
        <div>
            <div *ngFor="let result of results | async">
                <!-- -->
            </div>
        </div>
    </div>
  `,
  style: []
})
export class AppComponent {
    @debounce(1000)
    changeFn() {
        //... perform GET reguest
    }
}


// https://blog.bitsrc.io/6-useful-decorators-to-use-in-your-angular-projects-777e9b4c8c62