math.service.ts

import { create, all, MathJsStatic, format } from "mathjs";

/**
 * @description: 精确计算
 * @author ChenRui
 * @date 2021/6/9 9:44
 */
export class MathService {
  static DEFAULT_PRECISION = 20; // 默认保留的小数位数
  math: Partial<MathJsStatic> | any = create(all, { number: "BigNumber", precision: MathService.DEFAULT_PRECISION });

  /**
   * @description: 计算函数
   * @param: formula: 计算公式; precision: 保留的小数位数
   * @author ChenRui
   * @date 2021/6/9 9:42
   */
  evaluate(formula: string, precision: number = MathService.DEFAULT_PRECISION): void {
    const res: any = format(this.math.evaluate(formula), { notation: "fixed", precision: precision });
    return res;
  }
}
const mathService: MathService = new MathService();
export default mathService;