如何判断两个变量的值是否相等

亦凉 2022-01-20 06:51 248阅读 0赞

**1.相关代码**

function isObject (obj) {
        return Object.prototype.toString.call({}).slice(8,-1) === 'object'
    }
    function looseEqual (a, b) {
        if (a === b) return true
        const isObjectA = isObject(a)
        const isObjectB = isObject(b)
        if (isObjectA && isObjectB) {
          try {
            const isArrayA = Array.isArray(a)
            const isArrayB = Array.isArray(b)
            if (isArrayA && isArrayB) {
              return a.length === b.length && a.every((e, i) => {
                return looseEqual(e, b[i])
              })
            } else if (a instanceof Date && b instanceof Date) {
              return a.getTime() === b.getTime()
            } else if (!isArrayA && !isArrayB) {
              const keysA = Object.keys(a)
              const keysB = Object.keys(b)
              return keysA.length === keysB.length && keysA.every(key => {
                return looseEqual(a[key], b[key])
              })
            } else {
              return false
            }
          } catch (e) {
            return false
          }
        } else if (!isObjectA && !isObjectB) {
          return String(a) === String(b)
        } else {
          return false
        }
    }
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**2.使用场景**

//定义
        var a = NaN, a1 = NaN
        var b = new Date('2019'), b1 = new Date('2019')
        var c = {name:'jack',age:23}, c1 = {name:'jack',age:23}
        var d = [1,2,3], d1 = [1,2,3]
        
        //使用前
        a === a1 //false
        b === b1 //false
        c === c1 //false
        d === d1 //false
        
        //使用后
        looseEqual (a, a) //true
        looseEqual (b, b1) //true
        looseEqual (c, c1) //true
        looseEqual (d, d1) //true
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