JS 数据加减乘除， 不丢失精度

// 计算通用函数
// 核心工具函数
const _toInteger = (num) => {
    const str = num.toString()
    const pos = str.indexOf('.')
    const len = pos === -1 ? 0 : str.length - pos - 1
    const times = Math.pow(10, len)
    const integer = parseInt(str.replace('.', ''), 10)
    return { integer, times }
}

// 加法
const accAdd = (a, b) => {
    const { integer: intA, times: timesA } = _toInteger(a)
    const { integer: intB, times: timesB } = _toInteger(b)
    const maxTimes = Math.max(timesA, timesB)
    return (intA * (maxTimes / timesA) + intB * (maxTimes / timesB)) / maxTimes
}

// 减法
const accSub = (a, b) => {
    const { integer: intA, times: timesA } = _toInteger(a)
    const { integer: intB, times: timesB } = _toInteger(b)
    const maxTimes = Math.max(timesA, timesB)
    return (intA * (maxTimes / timesA) - intB * (maxTimes / timesB)) / maxTimes
}

// 乘法
const accMul = (a, b) => {
    const { integer: intA, times: timesA } = _toInteger(a)
    const { integer: intB, times: timesB } = _toInteger(b)
    return (intA * intB) / (timesA * timesB)
}

// 除法
const accDiv = (a, b) => {
    const { integer: intA, times: timesA } = _toInteger(a)
    const { integer: intB, times: timesB } = _toInteger(b)
    return (intA / intB) * (timesB / timesA)
}

export {
	accAdd,
	accSub,
	accMul,
	accDiv
}