@accordproject/markdown-common/lib/Stack.js

A framework for transforming markdown

/*
 * 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.
 */
'use strict';
/**
 * Manages a stack of objects
 */

class Stack {
  /**
  * Constructor
  */
  constructor() {
    this.clear();
  }
  /**
  * Clears the stack
  */


  clear() {
    this.stack = [];
  }
  /**
  * Returns the top of the stack or null if the stack is empty
  * @return {*} the top of the stack
  */


  peek() {
    if (this.stack.length === 0) {
      return null;
    }

    return this.stack[this.stack.length - 1];
  }
  /**
  * Pushes a new object to the top of the stack
  * @param {*} obj the node to push
  * @param {boolean} appendItem whether the item is also appended as a child to
  * the item at the top of the stack
  */


  push(obj) {
    let appendItem = arguments.length > 1 && arguments[1] !== undefined ? arguments[1] : true;

    if (appendItem) {
      this.append(obj);
    }

    this.stack.push(obj);
  }
  /**
  * Appends an object to the 'nodes' array of the item at the top of the stack
  * @param {*} obj the item to append to the top node
  */


  append(obj) {
    const top = this.peek();

    if (top && top.nodes) {
      top.nodes.push(obj);
    } else {
      throw new Error("Cannot append. Invalid stack: ".concat(JSON.stringify(this.stack, null, 4)));
    }
  }
  /**
  * Pops the top of the stack.
  * @return {*} the top of the stack
  */


  pop() {
    return this.stack.pop();
  }
  /**
  * Adds a new text leaf node.
  * @param {*} leaf the text node
  */


  addTextLeaf(leaf) {
    this.append({
      object: 'text',
      text: leaf.text,
      marks: leaf.marks
    });
  }

}

module.exports = Stack;