测试代码：

import {large_number} from "./large_number";

const {ccclass, property} = cc._decorator;

@ccclass
export default class NewClass extends cc.Component {

    @property(cc.Label)
    label: cc.Label = null;

    @property
    text: string = 'hello';

    // LIFE-CYCLE CALLBACKS:

    onLoad () {
        let large_number_es = new large_number();

        var b = [199999999];
        var res = large_number_es._ajust_bit_value(b);
        console.log("正确的显示，自动进位1999：");
        res = large_number_es.large_dis(res);
        console.log(res);

        var c = [1,0,0,0,0,0];
        var res = large_number_es._ajust_bit_value(c);
        console.log(res);
        console.log("正确的显示，消除前面的0000001");
        res = large_number_es.large_dis(res);
        console.log(res);

        var a = [1,1,5];
        var b = [0,999,5];
        console.log("加法1001+5999000：");
        res = large_number_es.large_add(a,b);
        console.log(res);

        var a = [1,1];
        var b = [0,999,5];
        console.log("减法错误:出现负数");
        res = large_number_es.large_minus(a,b);
        console.log(res);

        var a = [1,1,5,2,143,4];
        var b = [0,999,5,1,143,4];
        console.log("减法正确");
        res = large_number_es.large_minus(a,b);
        console.log(res);
        res = large_number_es.large_dis(res['cal']);
        console.log(res);

        var a = [1,1,9,2,3,4];
        var b = [1,1,9,2,3,4];
        console.log("减法相等");
        res = large_number_es.large_minus(a,b);
        console.log(res);
        res = large_number_es.large_dis(res['cal']);
        console.log(res);

        var a = [999,999];
        var bb = 9999;
        console.log("乘法");
        res = large_number_es.large_mul(a,bb);
        console.log(res);
        res = large_number_es.large_dis(res);
        console.log(res);
    }
}

 

计算的类：

export class large_number{
    public unit = ["","K","M","G","aa","ab","ac","ad"]; 
    //加法
    large_add(a,b){
        var temp = [];
        if(a.length<b.length)
        {
            while(a.length < b.length) {
                a.push(0);
            }
        }
        else
        {
            while(a.length > b.length) {
                b.push(0);
            }
        }
        for(var i = 0; i < a.length; i ++) {
            temp[i] = a[i] + b[i];   
        }
        var result = this._ajust_bit_value(temp);        
        return result;
    }

    /**
     * 减法:a-b 
     */
    large_minus(a,b){
        var temp = [];
        var result = {};
        if(a.length<b.length)
        {
            while(a.length < b.length) {
                a.push(0);
            }
        }
        else
        {
            while(a.length > b.length) {
                b.push(0);
            }
        }

        for(var i = 0; i < a.length; i ++) {
            temp[i] = a[i] - b[i];   
        }
        
        if(temp[temp.length -1] < 0)
        {
            //a小于b
            result['code'] = 400;
        }
        else
        {
            //把前面为0的都消除掉            
            var temp_cal = this._ajust_bit_value(temp);
            temp_cal = this._ajust_bit_value(temp_cal);
            result['code'] = 200;
            result['cal'] = temp_cal;
        }
        return result;
    }

   //乘法 a为大数据，b为乘数
    large_mul(a,b){
        var temp = [];       
        for(var i = 1; i < a.length; i ++) {
            console.log(a[i],b)
            temp[i-1] = Math.floor(((a[i] * 1000) + a[i-1])*b);
            
            temp[i] = 0;
            //temp[i] = Math.floor(temp[i]);
        }
        console.log(temp)
        var result = this._ajust_bit_value(temp);        
        return result;
    }

    //数值显示
    large_dis(a){
        var result:string = '0';
        if(a.length >= 2)
        {
            var result = String(a[a.length -1]) + '.' + String(this._format_num(a[a.length - 2])).substring(0,2) + this.unit[a.length -1];
        }
        else
        {
            var result = String(a[a.length -1]);
        }
        return result;
    }

    //转变成数值
    convert_number(array){
        let temp:number
        for(let i=1;i<array.length;i++)
        {

        }
    }
    
    //格式化：显示尾数数据
    _format_num(num) {
        if (num < 10) {
            return "00" + num;
        }
        else if(num < 100) {
            return "0" + num;
        }
        else {
            return "" + num;
        }
    }

    //格式化：运算后的数据
    _ajust_bit_value(bit_array){
        //加法
        for(var i = 0; i < bit_array.length; i ++) {
            while (bit_array[i] >= 1000) {
                bit_array[i] -= 1000;
                if (i + 1 >= bit_array.length) {
                    bit_array.push(0);                   
                }
                bit_array[i + 1] = bit_array[i + 1] + 1;
            }
        }
        //减法 
        if(bit_array.length >2)
        {            
            for(var j = bit_array.length -1; j > 0; j--)
            {
                if(bit_array[j] == 0)
                {                    
                    bit_array.splice(j,1);
                }
                else
                {
                    break;
                }
            }
        }

        for(var i = 0; i < bit_array.length; i ++) {
            while (bit_array[i] < 0) {
                bit_array[i] += 1000;
                bit_array[i+1] = bit_array[i+1] - 1;
            }
        }        
        
        return bit_array;
    }
}