node-nlp/examples/microsoft-bot/node_modules/chrono-node/src/refiners/EN/ENMergeDateTimeRefiner.js

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

/*
    
*/
var ParsedComponents = require('../../result').ParsedComponents;
var Refiner = require('../refiner').Refiner;

var PATTERN = new RegExp("^\\s*(T|at|after|before|on|of|,|-)?\\s*$");

var isDateOnly = exports.isDateOnly = function(result) {
    return !result.start.isCertain('hour');
}
    
var isTimeOnly = exports.isTimeOnly = function(result) {
    return !result.start.isCertain('month') && !result.start.isCertain('weekday');
}

var isAbleToMerge = exports.isAbleToMerge = function(text, prevResult, curResult) {
    var textBetween = text.substring(prevResult.index + prevResult.text.length, curResult.index);
    return textBetween.match(PATTERN);
}

var mergeDateTimeComponent = exports.mergeDateTimeComponent = function(dateComponent, timeComponent) {
    var dateTimeComponent = dateComponent.clone();

    if (timeComponent.isCertain('hour')) {
        dateTimeComponent.assign('hour', timeComponent.get('hour'));
        dateTimeComponent.assign('minute', timeComponent.get('minute'));
        dateTimeComponent.assign('second', timeComponent.get('second'));
    } else {
        dateTimeComponent.imply('hour', timeComponent.get('hour'));
        dateTimeComponent.imply('minute', timeComponent.get('minute'));
        dateTimeComponent.imply('second', timeComponent.get('second'));
    }


    if (timeComponent.isCertain('meridiem')) {
        dateTimeComponent.assign('meridiem', timeComponent.get('meridiem'));
    } else if (
        timeComponent.get('meridiem') !== undefined &&
        dateTimeComponent.get('meridiem') === undefined
    ) {
        dateTimeComponent.imply('meridiem', timeComponent.get('meridiem'));
    }

    if (dateTimeComponent.get('meridiem') == 1 && dateTimeComponent.get('hour') < 12) {
        if (timeComponent.isCertain('hour')) {
            dateTimeComponent.assign('hour', dateTimeComponent.get('hour') + 12);
        } else {
            dateTimeComponent.imply('hour', dateTimeComponent.get('hour') + 12);
        }
    }

    return dateTimeComponent;
}


function mergeResult(text, dateResult, timeResult){

    var beginDate = dateResult.start;
    var beginTime = timeResult.start;
    var beginDateTime = mergeDateTimeComponent(beginDate, beginTime);
    
    if (dateResult.end != null || timeResult.end != null) {
        
        var endDate   = dateResult.end == null ? dateResult.start : dateResult.end;            
        var endTime   = timeResult.end == null ? timeResult.start : timeResult.end;
        var endDateTime = mergeDateTimeComponent(endDate, endTime);
        
        if (dateResult.end == null && endDateTime.date().getTime() < beginDateTime.date().getTime()) {
            // Ex. 9pm - 1am
            if (endDateTime.isCertain('day')) {
                endDateTime.assign('day', endDateTime.get('day') + 1);
            } else {
                endDateTime.imply('day', endDateTime.get('day') + 1);
            }
        }

        dateResult.end = endDateTime;
    }

    dateResult.start = beginDateTime;    

    var startIndex = Math.min(dateResult.index, timeResult.index);
    var endIndex = Math.max(
            dateResult.index + dateResult.text.length, 
            timeResult.index + timeResult.text.length);
    
    dateResult.index = startIndex;
    dateResult.text  = text.substring(startIndex, endIndex);

    for (var tag in timeResult.tags) {
        dateResult.tags[tag] = true;
    }
    dateResult.tags['ENMergeDateAndTimeRefiner'] = true;
    return dateResult;
}

exports.Refiner = function ENMergeDateTimeRefiner() {
    Refiner.call(this);


    this.refine = function(text, results, opt) { 

        if (results.length < 2) return results;

        var mergedResult = [];
        var currResult = null;
        var prevResult = null;

        for (var i = 1; i < results.length; i++) {

            currResult = results[i];
            prevResult = results[i-1];
            
            if (isDateOnly(prevResult) && isTimeOnly(currResult) 
                    && isAbleToMerge(text, prevResult, currResult)) {
                
                prevResult = mergeResult(text, prevResult, currResult);
                currResult = results[i + 1];
                i += 1;
                
            } else if (isDateOnly(currResult) && isTimeOnly(prevResult)
                    && isAbleToMerge(text, prevResult, currResult)) {
                
                prevResult = mergeResult(text, currResult, prevResult);
                currResult = results[i + 1];
                i += 1;
            }
            
            mergedResult.push(prevResult);
        }

        if (currResult != null) {
            mergedResult.push(currResult);
        }

        return mergedResult;
    }
}