ES6-Array的一些方法

1..find() 寻找数组中某个满足条件的元素，当找到符合要求的元素时立马返回，，不再执行后面的操作

<script type="text/javascript">
    const  inventory = [
        {name:'mango',quantity:2},
        {name:'coconut',quantity:0},
        {name:'lemon',quantity:9}
    ];

    const coconut = inventory.find(fruit => {
        console.log(fruit.name);            //mango,coconut
        if(fruit.name === 'coconut') {
            return true;
        }
        return false;
    })
    console.log(coconut);     //{name: "coconut", quantity: 0}
</script>

2..findIndex()寻找数组项的下标

<script type="text/javascript">
    const  inventory = [
        {name:'mango',quantity:2},
        {name:'coconut',quantity:0},
        {name:'lemon',quantity:9}
    ];
    //.findIndex()
    const lemonIndex = inventory.findIndex(fruit => {
        if(fruit.name === 'lemon') {
            return true;
        }
        return false;
    })
    console.log(lemonIndex);       //2
</script>

3..some()数组中某一项满足条件时，即返回true;当找到满足条件项时即返回，不再继续执行

<script type="text/javascript">
    const  inventory = [
        {name:'mango',quantity:2},
        {name:'coconut',quantity:0},
        {name:'lemon',quantity:9}
    ];
    const isEnough = inventory.some(fruit => {
        console.log(fruit.name);           //mango,coconut
        if(fruit.quantity > 0) {
            return true;
        }
        return false; 
    });
    console.log(isEnough);       //true
</script>

4..every()数组中每一项都满足条件时才返回true；当执行到不满足条件项的时候立即结束，不执行后面的操作

<script type="text/javascript">
    const  inventory = [
        {name:'mango',quantity:2},
        {name:'coconut',quantity:0},
        {name:'lemon',quantity:9}
    ];
    const isAllEnough = inventory.every(fruit => {
        console.log(fruit.name);          //mango,coconut
        if(fruit.quantity > 0) {
            return true;
        }
        return false;
    });
    console.log(isAllEnough);           //false
</script>