node-nlp/examples/microsoft-bot/node_modules/chrono-node/src/parsers/EN/ENSlashDateFormatParser.js

Library for NLU (Natural Language Understanding) done in Node.js

/*
    Date format with slash "/" (also "-" and ".") between numbers
    - Tuesday 11/3/2015 
    - 11/3/2015
    - 11/3

    By default the paser us "middle-endien" format (US English),
    then fallback to little-endian if failed.
    - 11/3/2015 = November 3rd, 2015
    - 23/4/2015 = April 23th, 2015

    If "littleEndian" config is set, the parser will try the little-endian first. 
    - 11/3/2015 = March 11th, 2015
*/
var moment = require('moment');
var Parser = require('../parser').Parser;
var ParsedResult = require('../../result').ParsedResult;

var PATTERN = new RegExp('(\\W|^)' +
    '(?:' +
        '(?:on\\s*?)?' +
        '((?:sun|mon|tues?|wed(?:nes)?|thu(?:rs?)?|fri|sat(?:ur)?)(?:day)?)' +
        '\\s*\\,?\\s*' +
    ')?' +
    '([0-3]{0,1}[0-9]{1})[\\/\\.\\-]([0-3]{0,1}[0-9]{1})' +
    '(?:' +
        '[\\/\\.\\-]' +
        '([0-9]{4}\s*\,?\s*|[0-9]{2}\s*\,?\s*)' +
    ')?' +
    '(\\W|$)', 'i');

var DAYS_OFFSET = { 'sunday': 0, 'sun': 0, 'monday': 1, 'mon': 1,'tuesday': 2, 'wednesday': 3, 'wed': 3,
    'thursday': 4, 'thur': 4,'friday': 5, 'fri': 5,'saturday': 6, 'sat': 6,}


var OPENNING_GROUP = 1;
var ENDING_GROUP = 6;

var WEEKDAY_GROUP = 2;


var FIRST_NUMBERS_GROUP = 3;
var SECOND_NUMBERS_GROUP = 4;

var YEAR_GROUP = 5;

exports.Parser = function ENSlashDateFormatParser(config) {
    Parser.apply(this, arguments);
    config = config || {};
    var littleEndian  = config.littleEndian;
    var MONTH_GROUP = littleEndian ? SECOND_NUMBERS_GROUP : FIRST_NUMBERS_GROUP;
    var DAY_GROUP = littleEndian ? FIRST_NUMBERS_GROUP : SECOND_NUMBERS_GROUP;

    this.pattern = function () { return PATTERN; };
    this.extract = function(text, ref, match, opt){

        if(match[OPENNING_GROUP] == '/' || match[ENDING_GROUP] == '/') {
            // Long skip, if there is some overlapping like:
            // XX[/YY/ZZ]
            // [XX/YY/]ZZ
            match.index += match[0].length
            return;
        }

        var index = match.index + match[OPENNING_GROUP].length;
        var text = match[0].substr(match[OPENNING_GROUP].length, match[0].length - match[ENDING_GROUP].length);


        var result = new ParsedResult({
            text: text,
            index: index,
            ref: ref,
        });

        if(text.match(/^\d\.\d$/)) return;
        if(text.match(/^\d\.\d{1,2}\.\d{1,2}$/)) return;

        // MM/dd -> OK
        // MM.dd -> NG
        if(!match[YEAR_GROUP] && match[0].indexOf('/') < 0) return;

        var date = null;
        var year = match[YEAR_GROUP] || moment(ref).year() + '';
        var month = match[MONTH_GROUP];
        var day   = match[DAY_GROUP];

        month = parseInt(month);
        day  = parseInt(day);
        year = parseInt(year);

        if(month < 1 || month > 12) {
            if(month > 12) {
                // dd/mm/yyyy date format if day looks like a month, and month
                // looks like a day.
                if (day >= 1 && day <= 12 && month >= 13 && month <= 31) {
                    // unambiguous
                    var tday = month;
                    month = day;
                    day = tday;
                }
                else {
                    // both month and day are <= 12
                    return null;
                }
            }
        }
        if(day < 1 || day > 31) return null;

        if(year < 100){
            if (year > 50) {
                year = year + 1900;
            } else {
                year = year + 2000;
            }
        }

        result.start.assign('day', day);
        result.start.assign('month', month);
        result.start.assign('year', year);

        //Day of week
        if(match[WEEKDAY_GROUP]) {
            result.start.assign('weekday', DAYS_OFFSET[match[WEEKDAY_GROUP].toLowerCase()]);
        }

        result.tags['ENSlashDateFormatParser'] = true;
        return result;
    };
};