phylotree/src/formats/newick.js

A JavaScript library for developing applications and interactive visualizations involving [phylogenetic trees](https://en.wikipedia.org/wiki/Phylogenetic_tree), written as an extension of the [D3](http://d3js.org) [hierarchy layout](https://github.com/d3/

import { isLeafNode } from "../nodes";

/**
 * Parses a Newick string into an equivalent JSON representation that is
 * suitable for consumption by ``hierarchy``.
 *
 * Optionally accepts bootstrap values. Currently supports Newick strings with or without branch lengths,
 * as well as tagged trees such as
 *  ``(a,(b{TAG},(c{TAG},d{ANOTHERTAG})))``
 *
 * @param {String} nwk_str - A string representing a phylogenetic tree in Newick format.
 * @param {Object} bootstrap_values.
 * @returns {Object} An object with keys ``json`` and ``error``.
 */

function newickParser(nwk_str, options={}) {

  const bootstrap_values = true,
    int_or_float = /^-?\d+(\.\d+)?$/;
  let left_delimiter = options.left_delimiter ||  '{',
    right_delimiter = options.right_delimiter ||  '}';
  let clade_stack = [];

  function addNewTreeLevel() {
    let new_level = {
      name: null
    };

    let the_parent = clade_stack[clade_stack.length - 1];

    if (!("children" in the_parent)) {
      the_parent["children"] = [];
    }

    clade_stack.push(new_level);

    the_parent["children"].push(clade_stack[clade_stack.length - 1]);

    clade_stack[clade_stack.length - 1]["original_child_order"] =
      the_parent["children"].length;
  }

  function finishNodeDefinition() {

    let this_node = clade_stack.pop();

    this_node["name"] = current_node_name;

    if (bootstrap_values && "children" in this_node) {
      this_node["bootstrap_values"] = current_node_name;
    } else {
      this_node["name"] = current_node_name;
    }

    this_node["attribute"] = current_node_attribute;
    if(left_delimiter == "[" && current_node_annotation.includes("&&NHX")) {
      current_node_annotation
        .split(':')
        .slice(1)
        .forEach(annotation => {
          const [key, value] = annotation.split('=');
          this_node[key] = int_or_float.test(value) ? +value : value;
        });
    } else {
      this_node["annotation"] = current_node_annotation;
    }

    current_node_name = "";
    current_node_attribute = "";
    current_node_annotation = "";
  }

  function generateError(location) {
    return {
      json: null,
      error:
        "Unexpected '" +
        nwk_str[location] +
        "' in '" +
        nwk_str.substring(location - 20, location + 1) +
        "[ERROR HERE]" +
        nwk_str.substring(location + 1, location + 20) +
        "'"
    };
  }

  let automaton_state = 0;
  let current_node_name = "";
  let current_node_attribute = "";
  let current_node_annotation = "";
  let quote_delimiter = null;

  let name_quotes = {
    "'": 1,
    '"': 1
  };

  let tree_json = {
    name: "root"
  };

  clade_stack.push(tree_json);

  var space = /\s/;

  for (var char_index = 0; char_index < nwk_str.length; char_index++) {
    try {
      var current_char = nwk_str[char_index];
      switch (automaton_state) {
        case 0: {
          // look for the first opening parenthesis
          if (current_char == "(") {
            addNewTreeLevel();
            automaton_state = 1; // expecting node name
          }
          break;
        }
        case 1: // name
        case 3: {
          // branch length
          // reading name
          if (current_char == ":") {
            automaton_state = 3;
          } else if (current_char == "," || current_char == ")") {
            try {
              finishNodeDefinition();
              automaton_state = 1;
              if (current_char == ",") {
                addNewTreeLevel();
              }
            } catch (e) {
              return generateError(char_index);
            }
          } else if (current_char == "(") {
            if (current_node_name.length > 0) {
              return generateError(char_index);
            } else {
              addNewTreeLevel();
            }
          } else if (current_char in name_quotes) {
            if (
              automaton_state == 1 &&
              current_node_name.length === 0 &&
              current_node_attribute.length === 0 &&
              current_node_annotation.length === 0
            ) {
              automaton_state = 2;
              quote_delimiter = current_char;
              continue;
            }
            return generateError(char_index);
          } else {
            if (current_char == left_delimiter) {
              if (current_node_annotation.length) {
                return generateError(char_index);
              } else {
                automaton_state = 4;
              }
            } else {
              if (automaton_state == 3) {
                current_node_attribute += current_char;
              } else {
                if (space.test(current_char)) {
                  continue;
                }
                if (current_char == ";") {
                  // semicolon terminates tree definition
                  char_index = nwk_str.length;
                  break;
                }
                current_node_name += current_char;
              }
            }
          }

          break;
        }
        case 2: {
          // inside a quoted expression
          if (current_char == quote_delimiter) {
            if (char_index < nwk_str.length - 1) {
              if (nwk_str[char_index + 1] == quote_delimiter) {
                char_index++;
                current_node_name += quote_delimiter;
                continue;
              }
            }
            quote_delimiter = 0;
            automaton_state = 1;
            continue;
          } else {
            current_node_name += current_char;
          }
          break;
        }
        case 4: {
          // inside a comment / attribute
          if (current_char == right_delimiter) {
            automaton_state = 3;
          } else {
            if (current_char == left_delimiter) {
              return generateError(char_index);
            }
            current_node_annotation += current_char;
          }
          break;
        }
      }
    } catch (e) {
      return generateError(char_index);
    }
  }

  if (clade_stack.length != 1) {
    return generateError(nwk_str.length - 1);
  }

  return {
    json: tree_json,
    error: null
  };
}

/**
 * Return Newick string representation of a phylotree.
 *
 * @param {Function} annotator - Function to apply to each node, determining
 * what label is written (optional).
 * @param {Node} node - start at this node (default == root)
 * @returns {String} newick - Phylogenetic tree serialized as a Newick string.
 */


export function getNewick(annotator, root) {
  let self = this;

  if (!annotator) annotator = d => '';

  function nodeDisplay(n) {
    // Skip the node if it is hidden
    if (n.notshown) return;

    if (!isLeafNode(n)) {
      element_array.push("(");
      n.children.forEach(function(d, i) {
        if (i) {
          element_array.push(",");
        }
        nodeDisplay(d);
      });
      element_array.push(")");
    }

    if(n.data.name !== 'root') {
      const node_label = n.data.name.replaceAll("'", "''");

      // Surround the entire string with single quotes if it contains any
      // non-alphanumeric characters.
      if (/\W/.test(node_label)) {
        element_array.push("'" + node_label + "'");
      } else {
        element_array.push(node_label);
      }
    }
    element_array.push(annotator(n));

    let bl = self.branch_length_accessor(n);

    if (bl !== undefined) {
      element_array.push(":" + bl);
    }
  }

  let element_array = [];
  annotator = annotator || "";
  nodeDisplay(root || this.nodes);

  return element_array.join("")+";";
}

export default newickParser;