判断数据类型是否为true,false

简单给自己记录一下

let isNull = null;
let isUndefined = undefined;
let isNumber = 1;
let isString ='1';
let isEmptyString = '';
let isEmptyObject = {};
let isObject = { value : 1};
let isEmptyArray = [];
let isArray = [1];

即
isNull //f
isUndefined //f
isNumber //t
isString //t
isEmptyString //f

isObject //t
isEmptyObject //t
isArray //t
isEmptyArray //t
数组对象算长度
isArray && isArray.length //t
isObject && Object.keys(isObject).length // t
isEmptyObject && Object.keys(isEmptyObject).length //f
isEmptyArray && isEmptyArray.length //f

isNull ? console.log('isNull is true') : console.log('isNull is false');  //f
isUndefined ? console.log('isUndefined is true') : console.log('isUndefined is false'); //f
isNumber ? console.log('isNumber is true') : console.log('isNumber is false');  //t
isString ? console.log('isString is true') : console.log('isString is false');  //t
isEmptyString ? console.log('isEmptyString is true') : console.log('isEmptyString is false');  //f
isEmptyObject ? console.log('isEmptyObject is true') : console.log('isEmptyObject is false');  //t
isObject ? console.log('isObject is true') : console.log('isObject is false');  //t
isEmptyArray ? console.log('isEmptyArray is true') : console.log('isEmptyArray is false');  //t
isArray ? console.log('isArray is true') : console.log('isArray is false');  //t
isEmptyArray && isEmptyArray.length ? console.log('isEmptyArray && isEmptyArray.length is true') : console.log('isEmptyArray && isEmptyArray.length is false');  //f
isArray && isArray.length ? console.log('isArray && isArray.length is true') : console.log('isArray && isArray.length is false');  //t
isEmptyObject && Object.keys(isEmptyObject).length ? console.log('isEmptyObject && Object.keys(isEmptyObject).length is true') : console.log('isEmptyObject && Object.keys(isEmptyObject).length is false')  //f
isObject && Object.keys(isObject).length ? console.log('isObject && Object.keys(isObject).length is true') : console.log('isObject && Object.keys(isObject).length is false')  //t