Calculation/app/lib/material_calc.js

'use strict';

/**
 *
 *
 * @author Mai
 * @date
 * @version
 */

const math = require('mathjs');

class MaterialCalculate {
    constructor(ctx, stage_id_list, tenderInfo) {
        this.ctx = ctx;
        this.stageList = stage_id_list;
        this.percentReg = /[0-9]+%/g;
        this.tenderInfo = tenderInfo;
    }

    /**
     * 获取 计算基数
     * @returns {Promise<void>}
     */
    async getCalcBase() {
        if (this.bases) { return; }
        const stage_list = await this.ctx.service.stage.getStageMsgByStageId(this.stageList);
        const bases = await this.ctx.service.stage.getMaterialCalcBase(stage_list, this.tenderInfo);
        this.bases = bases.sort(function(a, b) {
            return a.sort - b.sort;
            // if (a && b) {
            //     return b.code.indexOf(a.code) >= 0 ? 1 : 0;
            // } else {
            //     return 0;
            // }
        });
        for (const b of this.bases) {
            b.reg = new RegExp(b.code, 'igm');
        }
    }

    _calculateExpr(expr) {
        try {
            let formula = expr;
            for (const b of this.bases) {
                formula = formula.replace(b.reg, b.value);
            }
            const percent = formula.match(this.percentReg);
            if (percent) {
                for (const p of percent) {
                    const v = math.eval(p.replace('%', '/100'));
                    formula = formula.replace(p, v);
                }
            }
            const value = parseFloat(math.eval(formula));
            return value;
        } catch (err) {
            return 0;
        }
    }

    async calculateExpr(expr) {
        await this.getCalcBase();
        return this._calculateExpr(expr);
    }
}

module.exports = MaterialCalculate;