SCCommon/util/src/math.ts

/* eslint-disable no-param-reassign */
/* eslint-disable no-restricted-globals */
// 判断传入的是否是数字或者可转为数字的字符串
export const isNumber = (value: string | number): boolean => {
  return /^(-|\+)?\d+(\.\d+)?$/.test(value as string);
};

export const innerRound = (
  num: number,
  length: number,
  decimal: number
): number => {
  let value;
  let pre = 1;
  if (length === 0) return num;
  if (num < 0) pre = -1; // 负数的时候先变成正数
  num *= pre;
  const n = 10 ** length;
  value = Math.round(num * n);
  if (length <= decimal) {
    return (value / n) * pre;
  }
  value = Math.round(value / 10 ** (length - decimal));
  return (value / 10 ** decimal) * pre;
};

// 4舍5入
export const roundForObj = (
  obj: string | number | undefined | null,
  decimal: number
): number => {
  let value;
  if (obj === undefined || obj === null || isNaN(obj as number)) return 0;
  const length = 10;
  if (obj === +obj) {
    value = innerRound(obj, length, decimal);
  } else {
    value = innerRound(Number(obj), length, decimal);
  }
  return value;
};

export const roundToString = (
  obj: string | number,
  decimal: number
): string => {
  const value = roundForObj(obj, decimal);
  return value.toFixed(decimal);
};

// 取单位前的数字，并转换成整数
export const getNumberFromUnit = (unit: string): number => {
  const reg = new RegExp('^[0-9]+');
  if (unit && reg.test(unit)) {
    const arr: any = unit.match(reg);
    return parseInt(arr[0], 10);
  }
  return 1;
};