Bool对象
- toString() 把逻辑值转字符串
- valueOf() 返回bool对象的原始值 true 或者 false
let bool = new Boolean(1);
console.log(bool); // [Boolean: true]
console.log(bool.toString()); // true
console.log(bool.valueOf()); // true
Math对象
- random()：随机数Math.random()
// random[0,1) 的随机数
let randomNum = Math.random();
console.log(randomNum); // 0.26479285938843655 随机一个数
- round(n)：返回最接近的整数
// round 四舍五入
console.log(Math.round(-0.3)); // -0
console.log(Math.round(-0.5)); // -0
console.log(Math.round(-0.8)); // -1
console.log(Math.round(0.3)); // 0
console.log(Math.round(0.5)); // 1
console.log(Math.round(0.8)); // 1
console.log(Math.round(1.3)); // 1
console.log(Math.round(1.5)); // 2
console.log(Math.round(1.8)); // 2
- ceil(n)：向上取整
// ceil 向上取整
console.log('ceil',Math.ceil(-0.3)); //-0
console.log('ceil',Math.ceil(-0.5)); //-0
console.log('ceil',Math.ceil(-0.8)); //-0
console.log('ceil',Math.ceil(0.3)); //1
console.log('ceil',Math.ceil(0.5)); //1
console.log('ceil',Math.ceil(0.8)); //1
console.log('ceil',Math.ceil(1.3)); //2
console.log('ceil',Math.ceil(1.5)); //2
console.log('ceil',Math.ceil(1.8)); //2
- floor(n)：向下(靠近0)取整
// floor向下取整
console.log(Math.floor(-0.3)); //-1
console.log(Math.floor(-0.5)); //-1
console.log(Math.floor(-0.8)); //-1
console.log(Math.floor(0.3)); //0
console.log(Math.floor(0.5)); //0
console.log(Math.floor(0.8)); //0
console.log(Math.floor(1.3)); //1
console.log(Math.floor(1.5)); //1
console.log(Math.floor(1.8)); //1
Number对象
- toString()：把数字转字符串
- valueOf()：返回Number对象的基本数字值 true 或者 false
let number = 105;
console.log(number); //105
console.log(number.toString()); //105
console.log(number.valueOf()); //105
Date对象
构造函数实例化之后才能用
