chrono-node/src/parsers/EN/ENTimeAgoFormatParser.js

A natural language date parser in Javascript

/*


*/

var moment = require('moment');
var Parser = require('../parser').Parser;
var ParsedResult = require('../../result').ParsedResult;
var util  = require('../../utils/EN');

var PATTERN = new RegExp('' +
    '(\\W|^)' +
    '(?:within\\s*)?' +
    '(' + util.INTEGER_WORDS_PATTERN + '|[0-9]+|an?(?:\\s*few)?|half(?:\\s*an?)?)\\s*' +
    '(seconds?|min(?:ute)?s?|hours?|weeks?|days?|months?|years?)\\s*' +
    '(?:ago|before|earlier)(?=(?:\\W|$))', 'i');

var STRICT_PATTERN = new RegExp('' +
    '(\\W|^)' +
    '(?:within\\s*)?' +
    '([0-9]+|an?)\\s*' +
    '(seconds?|minutes?|hours?|days?)\\s*' +
    'ago(?=(?:\\W|$))', 'i');

exports.Parser = function ENTimeAgoFormatParser(){
    Parser.apply(this, arguments);

    this.pattern = function() {
        return this.isStrictMode()? STRICT_PATTERN : PATTERN;
    };

    this.extract = function(text, ref, match, opt){

        if (match.index > 0 && text[match.index-1].match(/\w/)) return null;

        var text = match[0];
        text  = match[0].substr(match[1].length, match[0].length - match[1].length);
        index = match.index + match[1].length;

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

        var num = match[2].toLowerCase() ;
        if (util.INTEGER_WORDS[num] !== undefined) {
            num = util.INTEGER_WORDS[num];
        } else if(num === 'a' || num === 'an'){
            num = 1;
        } else if (num.match(/few/)) {
            num = 3;
        } else if (num.match(/half/)) {
            num = 0.5;
        } else {
            num = parseInt(num);
        }

        var date = moment(ref);

        if (match[3].match(/hour|min|second/i)) {
            if (match[3].match(/hour/i)) {

                date.add(-num, 'hour');

            } else if (match[3].match(/min/i)) {

                date.add(-num, 'minute');

            } else if (match[3].match(/second/i)) {

                date.add(-num, 'second');
            }

            result.start.imply('day', date.date());
            result.start.imply('month', date.month() + 1);
            result.start.imply('year', date.year());
            result.start.assign('hour', date.hour());
            result.start.assign('minute', date.minute());
            result.start.assign('second', date.second());
            result.tags['ENTimeAgoFormatParser'] = true;
            return result;
        }

        if (match[3].match(/week/i)) {
            date.add(-num, 'week');

            result.start.imply('day', date.date());
            result.start.imply('month', date.month() + 1);
            result.start.imply('year', date.year());
            result.start.imply('weekday', date.day());
            return result;
        }

        if (match[3].match(/day/i)) {
            date.add(-num, 'd');
        }

        if (match[3].match(/month/i)) {
            date.add(-num, 'month');
        }

        if (match[3].match(/year/i)) {

            date.add(-num, 'year');
        }

        result.start.assign('day', date.date());
        result.start.assign('month', date.month() + 1);
        result.start.assign('year', date.year());
        return result;

    };
}