ingenta-lens/substance/data/property.js

A novel way of seeing content.

"use strict";

var _ = require("underscore");

var Property = function(graph, path) {
  if (!path) {
    throw new Error("Illegal argument: path is null/undefined.");
  }

  this.graph = graph;
  this.schema = graph.schema;

  _.extend(this, this.resolve(path));
};

Property.Prototype = function() {

  this.resolve = function(path) {
    var node = this.graph;
    var parent = node;
    var type = "graph";

    var key;
    var value;

    var idx = 0;
    for (; idx < path.length; idx++) {

      // TODO: check if the property references a node type
      if (type === "graph" || this.schema.types[type] !== undefined) {
        // remember the last node type
        parent = this.graph.get(path[idx]);

        if (parent === undefined) {
          //throw new Error("Key error: could not find element for path " + JSON.stringify(path));
          return undefined;
        }

        node = parent;
        type = this.schema.properties(parent.type);
        value = node;
        key = undefined;
      } else {
        if (parent === undefined) {
          //throw new Error("Key error: could not find element for path " + JSON.stringify(path));
          return undefined;
        }
        key = path[idx];
        var propName = path[idx];
        type = type[propName];
        value = parent[key];

        if (idx < path.length-1) {
          parent = parent[propName];
        }
      }
    }

    return {
      node: node,
      parent: parent,
      type: type,
      key: key,
      value: value
    };

  };

  this.get = function() {
    if (this.key !== undefined) {
      return this.parent[this.key];
    } else {
      return this.node;
    }
  };

  this.set = function(value) {
    if (this.key !== undefined) {
      this.parent[this.key] = this.schema.parseValue(this.baseType, value);
    } else {
      throw new Error("'set' is only supported for node properties.");
    }
  };

};
Property.prototype = new Property.Prototype();
Object.defineProperties(Property.prototype, {
  baseType: {
    get: function() {
      if (_.isArray(this.type)) return this.type[0];
      else return this.type;
    }
  },
  path: {
    get: function() {
      return [this.node.id, this.key];
    }
  }
});

module.exports = Property;