ES6简单map结构实现

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class myMap{
	constructor(obj){
		this.obj = {}
        this.length = 0
        if(Array.isArray(obj)){
            obj.every((item, index, arr) => {
                if(Array.isArray(item)){
                    this.obj[item[0]] = item[1]
                    this.length += 1
                    return true
                }else{
                    this.obj = {}
                    this.length = 0
                    return false
                }
            })
        }
    }

    has(key){
        return this.obj.hasOwnProperty(key)
    }

    size(){
        return this.length
    }

    get(key){
        if(this.has(key)){
            return this.obj[key]
        }
    }

    set(key, value){
        if(this.has(key)){
            this.obj[key] = value
        }else{
            this.obj[key] = value
            this.length += 1
        }
        return this
    }

    keys(){
        return Object.keys(this.obj)
    }

    values(){
        return Object.values(this.obj)
    }

    entries(){
        return Object.entries(this.obj)
    }

    delete(key){
        if(this.has(key)){
            this.length -= 1
            delete this.obj[key]
        }
        return this
    }

    clear(){
        this.obj = {}
        this.length = 0
        return this
    }
}

let my_Map = new myMap()
my_Map.set('foo', true).set('foo2', false).set('foo2', 1)
console.log(my_Map);

let map = new Map()
map.set('foo', true)
map.set('foo2', false)
console.log(map);