1.二进制和八进制
console.log("二进制",0b101); //5
console.log("八进制",0o007); //7

2.Number
是否有限
console.log(Number.isFinite(Infinity)) //false
console.log(Number.isFinite(NaN)) //false
console.log(Number.isFinite(null)) //false
console.log(Number.isFinite(10)) //true

判断NAN
console.log(Number.isNaN(10)) //false
console.log(Number.isNaN(true)) //false
console.log(Number.isNaN(1/'a')) //true

判断整数
console.log(Number.isInteger(10.1)) //false
console.log(Number.isInteger(10.0)) //true
console.log(Number.isInteger('10.0')) //false
console.log(Number.isInteger('10')) //false

表示一个最小的数，等于2的52次方
console.log(Number.EPSILON) 
console.log(Math.pow(2,-52) === Number.EPSILON)
console.log(Number.EPSILON.toFixed(20))

console.log(0.1+0.2 === 0.3) //false js浮点计算有问题
console.log(0.1+0.2 - 0.3 < Number.EPSILON) //false

最大整数，最小整数，安全范围
Number.MAX_SAFE_INTEGER 
Number.MIN_SAFE_INTEGER
Number.isSafeInteger()
console.log(Number.MAX_SAFE_INTEGER);
console.log(Math.pow(2,53))
console.log(Math.pow(2,53)==Math.pow(2,53)+1) //true JS超出后计算不精确
console.log(Number.MAX_SAFE_INTEGER+1 == Math.pow(2,53))

3.Math
Math.trunc()去除小数
console.log(Math.trunc(3.14)) //3
console.log(Math.trunc(-3.14)) //-3

Math.sign()判断是不是正数
console.log(Math.sign(10)); //1
console.log(Math.sign(-100));//-1
console.log(Math.sign(0));//0
console.log(Math.sign(NaN));//NaN

求一个数的立方根
console.log(Math.cbrt(8))//2

4.**运算符
//指数运算符**
console.log(10**2) //100
console.log(2**2**3) //256
 

 二进制和八进制的转换