/*************************************************************
 *
 *  Copyright (c) 2018 The MathJax Consortium
 *
 *  Licensed under the Apache License, Version 2.0 (the "License");
 *  you may not use this file except in compliance with the License.
 *  You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 *  Unless required by applicable law or agreed to in writing, software
 *  distributed under the License is distributed on an "AS IS" BASIS,
 *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *  See the License for the specific language governing permissions and
 *  limitations under the License.
 */

/**
 * @fileoverview  Implements a lightweight DOM adaptor
 *
 * @author dpvc@mathjax.org (Davide Cervone)
 */

import {LiteNode} from './Element.js';

/************************************************************/
/**
 * Implements a lightweight DocumentFragment or NodeList replacement
 *
 * @template N  The HTMLElement node class
 */
export class LiteList<N> {
    /**
     * The nodes held in the fragment
     */
    public nodes: N[] = [];

    /**
     * @param {N[]} children  The children for the fragment
     * @constructor
     */
    constructor(children: N[]) {
        this.nodes = [...children];
    }

    /**
     * @param {N} node  A node to append to the fragment
     */
    public append(node: N) {
        this.nodes.push(node);
    }

    /**
     * Make this class iterable (so it can be used with Array.from())
     */
    public [Symbol.iterator](): Iterator<LiteNode> {
        let i = 0;
        return {
            next() {
                return (i === this.nodes.length ?
                        {value: null, done: true} :
                        {value: this.nodes[i++], done: false}) as IteratorResult<LiteNode>;
            }
        };
    }

}