docsify/lib/plugins/front-matter.js

(function () {
  /**
   * Fork https://github.com/egoist/docute/blob/master/src/utils/yaml.js
   */
  /* eslint-disable */
  /*
  YAML parser for Javascript
  Author: Diogo Costa
  This program is released under the MIT License as follows:
  Copyright (c) 2011 Diogo Costa (costa.h4evr@gmail.com)
  Permission is hereby granted, free of charge, to any person obtaining a copy
   of this software and associated documentation files (the "Software"), to deal
   in the Software without restriction, including without limitation the rights
   to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
   copies of the Software, and to permit persons to whom the Software is
   furnished to do so, subject to the following conditions:
  The above copyright notice and this permission notice shall be included in
   all copies or substantial portions of the Software.
  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
   IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
   FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
   AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
   LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
   OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
   THE SOFTWARE.
  */

  /**
   * @name YAML
   * @namespace
  */

  var errors = [],
    reference_blocks = [],
    processing_time = 0,
    regex = {
      regLevel: new RegExp('^([\\s\\-]+)'),
      invalidLine: new RegExp('^\\-\\-\\-|^\\.\\.\\.|^\\s*#.*|^\\s*$'),
      dashesString: new RegExp('^\\s*\\"([^\\"]*)\\"\\s*$'),
      quotesString: new RegExp("^\\s*\\'([^\\']*)\\'\\s*$"),
      float: new RegExp('^[+-]?[0-9]+\\.[0-9]+(e[+-]?[0-9]+(\\.[0-9]+)?)?$'),
      integer: new RegExp('^[+-]?[0-9]+$'),
      array: new RegExp('\\[\\s*(.*)\\s*\\]'),
      map: new RegExp('\\{\\s*(.*)\\s*\\}'),
      key_value: new RegExp('([a-z0-9_-][ a-z0-9_-]*):( .+)', 'i'),
      single_key_value: new RegExp('^([a-z0-9_-][ a-z0-9_-]*):( .+?)$', 'i'),
      key: new RegExp('([a-z0-9_-][ a-z0-9_-]+):( .+)?', 'i'),
      item: new RegExp('^-\\s+'),
      trim: new RegExp('^\\s+|\\s+$'),
      comment: new RegExp('([^\\\'\\"#]+([\\\'\\"][^\\\'\\"]*[\\\'\\"])*)*(#.*)?')
    };

  /**
    * @class A block of lines of a given level.
    * @param {int} lvl The block's level.
    * @private
    */
  function Block(lvl) {
    return {
      /* The block's parent */
      parent: null,
      /* Number of children */
      length: 0,
      /* Block's level */
      level: lvl,
      /* Lines of code to process */
      lines: [],
      /* Blocks with greater level */
      children: [],
      /* Add a block to the children collection */
      addChild: function(obj) {
        this.children.push(obj);
        obj.parent = this;
        ++this.length;
      }
    }
  }

  function parser(str) {
    var regLevel = regex['regLevel'];
    var invalidLine = regex['invalidLine'];
    var lines = str.split('\n');
    var m;
    var level = 0,
      curLevel = 0;

    var blocks = [];

    var result = new Block(-1);
    var currentBlock = new Block(0);
    result.addChild(currentBlock);
    var levels = [];
    var line = '';

    blocks.push(currentBlock);
    levels.push(level);

    for (var i = 0, len = lines.length; i < len; ++i) {
      line = lines[i];

      if (line.match(invalidLine)) {
        continue
      }

      if ((m = regLevel.exec(line))) {
        level = m[1].length;
      } else { level = 0; }

      if (level > curLevel) {
        var oldBlock = currentBlock;
        currentBlock = new Block(level);
        oldBlock.addChild(currentBlock);
        blocks.push(currentBlock);
        levels.push(level);
      } else if (level < curLevel) {
        var added = false;

        var k = levels.length - 1;
        for (; k >= 0; --k) {
          if (levels[k] == level) {
            currentBlock = new Block(level);
            blocks.push(currentBlock);
            levels.push(level);
            if (blocks[k].parent != null) { blocks[k].parent.addChild(currentBlock); }
            added = true;
            break
          }
        }

        if (!added) {
          errors.push('Error: Invalid indentation at line ' + i + ': ' + line);
          return
        }
      }

      currentBlock.lines.push(line.replace(regex['trim'], ''));
      curLevel = level;
    }

    return result
  }

  function processValue(val) {
    val = val.replace(regex['trim'], '');
    var m = null;

    if (val == 'true') {
      return true
    } else if (val == 'false') {
      return false
    } else if (val == '.NaN') {
      return Number.NaN
    } else if (val == 'null') {
      return null
    } else if (val == '.inf') {
      return Number.POSITIVE_INFINITY
    } else if (val == '-.inf') {
      return Number.NEGATIVE_INFINITY
    } else if ((m = val.match(regex['dashesString']))) {
      return m[1]
    } else if ((m = val.match(regex['quotesString']))) {
      return m[1]
    } else if ((m = val.match(regex['float']))) {
      return parseFloat(m[0])
    } else if ((m = val.match(regex['integer']))) {
      return parseInt(m[0])
    } else if (!isNaN((m = Date.parse(val)))) {
      return new Date(m)
    } else if ((m = val.match(regex['single_key_value']))) {
      var res = {};
      res[m[1]] = processValue(m[2]);
      return res
    } else if ((m = val.match(regex['array']))) {
      var count = 0,
        c = ' ';
      var res = [];
      var content = '';
      var str = false;
      for (var j = 0, lenJ = m[1].length; j < lenJ; ++j) {
        c = m[1][j];
        if (c == "'" || c == '"') {
          if (str === false) {
            str = c;
            content += c;
            continue
          } else if ((c == "'" && str == "'") || (c == '"' && str == '"')) {
            str = false;
            content += c;
            continue
          }
        } else if (str === false && (c == '[' || c == '{')) {
          ++count;
        } else if (str === false && (c == ']' || c == '}')) {
          --count;
        } else if (str === false && count == 0 && c == ',') {
          res.push(processValue(content));
          content = '';
          continue
        }

        content += c;
      }

      if (content.length > 0) { res.push(processValue(content)); }
      return res
    } else if ((m = val.match(regex['map']))) {
      var count = 0,
        c = ' ';
      var res = [];
      var content = '';
      var str = false;
      for (var j = 0, lenJ = m[1].length; j < lenJ; ++j) {
        c = m[1][j];
        if (c == "'" || c == '"') {
          if (str === false) {
            str = c;
            content += c;
            continue
          } else if ((c == "'" && str == "'") || (c == '"' && str == '"')) {
            str = false;
            content += c;
            continue
          }
        } else if (str === false && (c == '[' || c == '{')) {
          ++count;
        } else if (str === false && (c == ']' || c == '}')) {
          --count;
        } else if (str === false && count == 0 && c == ',') {
          res.push(content);
          content = '';
          continue
        }

        content += c;
      }

      if (content.length > 0) { res.push(content); }

      var newRes = {};
      for (var j = 0, lenJ = res.length; j < lenJ; ++j) {
        if ((m = res[j].match(regex['key_value']))) {
          newRes[m[1]] = processValue(m[2]);
        }
      }

      return newRes
    } else { return val }
  }

  function processFoldedBlock(block) {
    var lines = block.lines;
    var children = block.children;
    var str = lines.join(' ');
    var chunks = [str];
    for (var i = 0, len = children.length; i < len; ++i) {
      chunks.push(processFoldedBlock(children[i]));
    }
    return chunks.join('\n')
  }

  function processLiteralBlock(block) {
    var lines = block.lines;
    var children = block.children;
    var str = lines.join('\n');
    for (var i = 0, len = children.length; i < len; ++i) {
      str += processLiteralBlock(children[i]);
    }
    return str
  }

  function processBlock(blocks) {
    var m = null;
    var res = {};
    var lines = null;
    var children = null;
    var currentObj = null;

    var level = -1;

    var processedBlocks = [];

    var isMap = true;

    for (var j = 0, lenJ = blocks.length; j < lenJ; ++j) {
      if (level != -1 && level != blocks[j].level) { continue }

      processedBlocks.push(j);

      level = blocks[j].level;
      lines = blocks[j].lines;
      children = blocks[j].children;
      currentObj = null;

      for (var i = 0, len = lines.length; i < len; ++i) {
        var line = lines[i];

        if ((m = line.match(regex['key']))) {
          var key = m[1];

          if (key[0] == '-') {
            key = key.replace(regex['item'], '');
            if (isMap) {
              isMap = false;
              if (typeof res.length === 'undefined') {
                res = [];
              }
            }
            if (currentObj != null) { res.push(currentObj); }
            currentObj = {};
            isMap = true;
          }

          if (typeof m[2] != 'undefined') {
            var value = m[2].replace(regex['trim'], '');
            if (value[0] == '&') {
              var nb = processBlock(children);
              if (currentObj != null) { currentObj[key] = nb; }
              else { res[key] = nb; }
              reference_blocks[value.substr(1)] = nb;
            } else if (value[0] == '|') {
              if (currentObj != null)
                { currentObj[key] = processLiteralBlock(children.shift()); }
              else { res[key] = processLiteralBlock(children.shift()); }
            } else if (value[0] == '*') {
              var v = value.substr(1);
              var no = {};

              if (typeof reference_blocks[v] == 'undefined') {
                errors.push("Reference '" + v + "' not found!");
              } else {
                for (var k in reference_blocks[v]) {
                  no[k] = reference_blocks[v][k];
                }

                if (currentObj != null) { currentObj[key] = no; }
                else { res[key] = no; }
              }
            } else if (value[0] == '>') {
              if (currentObj != null)
                { currentObj[key] = processFoldedBlock(children.shift()); }
              else { res[key] = processFoldedBlock(children.shift()); }
            } else {
              if (currentObj != null) { currentObj[key] = processValue(value); }
              else { res[key] = processValue(value); }
            }
          } else {
            if (currentObj != null) { currentObj[key] = processBlock(children); }
            else { res[key] = processBlock(children); }
          }
        } else if (line.match(/^-\s*$/)) {
          if (isMap) {
            isMap = false;
            if (typeof res.length === 'undefined') {
              res = [];
            }
          }
          if (currentObj != null) { res.push(currentObj); }
          currentObj = {};
          isMap = true;
          continue
        } else if ((m = line.match(/^-\s*(.*)/))) {
          if (currentObj != null) { currentObj.push(processValue(m[1])); }
          else {
            if (isMap) {
              isMap = false;
              if (typeof res.length === 'undefined') {
                res = [];
              }
            }
            res.push(processValue(m[1]));
          }
          continue
        }
      }

      if (currentObj != null) {
        if (isMap) {
          isMap = false;
          if (typeof res.length === 'undefined') {
            res = [];
          }
        }
        res.push(currentObj);
      }
    }

    for (var j = processedBlocks.length - 1; j >= 0; --j) {
      blocks.splice.call(blocks, processedBlocks[j], 1);
    }

    return res
  }

  function semanticAnalysis(blocks) {
    var res = processBlock(blocks.children);
    return res
  }

  function preProcess(src) {
    var m;
    var lines = src.split('\n');

    var r = regex['comment'];

    for (var i in lines) {
      if ((m = lines[i].match(r))) {
        /*                var cmt = "";
              if(typeof m[3] != "undefined")
                  lines[i] = m[1];
              else if(typeof m[3] != "undefined")
                  lines[i] = m[3];
              else
                  lines[i] = "";
                  */
        if (typeof m[3] !== 'undefined') {
          lines[i] = m[0].substr(0, m[0].length - m[3].length);
        }
      }
    }

    return lines.join('\n')
  }

  function load(str) {
    errors = [];
    reference_blocks = [];
    processing_time = new Date().getTime();
    var pre = preProcess(str);
    var doc = parser(pre);
    var res = semanticAnalysis(doc);
    processing_time = new Date().getTime() - processing_time;

    return res
  }

  /**
   * Fork https://github.com/egoist/docute/blob/master/src/utils/front-matter.js
   */

  var optionalByteOrderMark = '\\ufeff?';
  var pattern =
    '^(' +
    optionalByteOrderMark +
    '(= yaml =|---)' +
    '$([\\s\\S]*?)' +
    '(?:\\2|\\.\\.\\.)' +
    '$' +
    '' +
    '(?:\\n)?)';
  // NOTE: If this pattern uses the 'g' flag the `regex` variable definition will
  // need to be moved down into the functions that use it.
  var regex$1 = new RegExp(pattern, 'm');

  function extractor(string) {
    string = string || '';

    var lines = string.split(/(\r?\n)/);
    if (lines[0] && /= yaml =|---/.test(lines[0])) {
      return parse(string)
    } else {
      return { attributes: {}, body: string }
    }
  }

  function parse(string) {
    var match = regex$1.exec(string);

    if (!match) {
      return {
        attributes: {},
        body: string
      }
    }

    var yaml = match[match.length - 1].replace(/^\s+|\s+$/g, '');
    var attributes = load(yaml) || {};
    var body = string.replace(match[0], '');

    return { attributes: attributes, body: body, frontmatter: yaml }
  }

  var install = function (hook, vm) {
    // Used to remove front matter from embedded pages if installed.
    vm.config.frontMatter = {};
    vm.config.frontMatter.installed = true;
    vm.config.frontMatter.parseMarkdown = function (content) {
      var ref = extractor(content);
      var body = ref.body;
      return body;
    };

    hook.beforeEach(function (content) {
      var ref = extractor(content);
      var attributes = ref.attributes;
      var body = ref.body;

      vm.frontmatter = attributes;

      return body;
    });
  };

  $docsify.plugins = [].concat(install, $docsify.plugins);

}());