@entestat/formula/silk/DateHelper.js

fast excel formula parser

const {FormulaHelpers} = require("../formulas/helpers");
const {LocalDate} = require("./LocalDate");

function addToDate(lDate, numOffset){
    return (new LocalDate()).fromMoment(lDate.asMoment().add(numOffset, 'days'));
}

function subFromDate(lDate, numOffset){
    return addToDate(lDate, -numOffset);
}

const DateHelper = {
    isDate(val){
        return val && val.constructor && val.constructor.name === "LocalDate";
    },
    isNullDate(val){
        return val == null || val === "";
    },

    isNullableDate(val){
        return val == null || val === "" || DateHelper.isDate(val);
    },

    dateCompareOp(value1, infix, value2){
        const firstIsDate = DateHelper.isDate(value1);
        const secondIsDate = DateHelper.isDate(value2);
        const firstIsNull = DateHelper.isNullDate(value1);
        const secondIsNull = DateHelper.isNullDate(value2);

        if(firstIsNull || secondIsNull){
            return false;
        }

        const first = value1.asMoment();
        const second = value2.asMoment();

        switch (infix) {
            case '=':
                return first.isSame(second);
            case '>':
                return first.after(second);
            case '<':
                return second.after(first);
            case '<>':
                return !first.isSame(second);
            case '<=':
                return first.isSame(second) ||  second.after(first);
            case '>=':
                return first.isSame(second) ||  first.after(second);
        }
        throw Error('Infix.compareOp: Should not reach here.');
    },

    dateOp(infix, value1, value2){
        const firstIsDate = DateHelper.isDate(value1);
        const secondIsDate = DateHelper.isDate(value2);

        if(infix === "+"){
            if(firstIsDate){
                return addToDate(value1, FormulaHelpers.acceptNumber(value2));
            } else {
                if(!secondIsDate){
                    throw new Error(`Unrecognized date operation`);
                }
                return addToDate(value2, FormulaHelpers.acceptNumber(value1));
            }
        } else if(infix === "-"){
            if(firstIsDate){
                return subFromDate(value1, FormulaHelpers.acceptNumber(value2));
            } else {
                throw new Error(`Unrecognized date operation`);
            }
        }
        throw new Error(`Unrecognized date operation`);
    }
}

module.exports = {
    DateHelper
};