import {arr} from './arr.js';
//abbrev for wait for attribute change
export function wfac(el: Element, attributeNameOrNames: string | Array<string>, test?: (mr: MutationRecord, el: Element, attributeNameOrNames: string | Array<string>) => boolean){
    //kind of limited, promises only seem to support one time only events. 
    const attrNames = arr(attributeNameOrNames);
    return new Promise((resolve, reject) =>{
        const observer = new MutationObserver(mutations => {
            mutations.forEach(mutation => {
                const {attributeName} = mutation;
                if(attributeName === null) return;
                if(attrNames.includes(attributeName)){
                    if(test){
                        if(test(mutation, el, attributeNameOrNames)){
                            observer.disconnect();
                            resolve(mutation);
                        }
                    }else{
                        observer.disconnect();
                        resolve(mutation);
                    }
                }
            });    
        });
        const observerConfig = {
            attributes: true, 
            attributeFilter: attrNames,
        } as MutationObserverInit;
        observer.observe(el, observerConfig);
    });

}