javascript -- 高级API

javascript 部分高级API

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1.instanceof
判断 A 是否等于 B

<script>
var arr = [];
var obj = {};
//判断arr是否等于Array
conlose.log(arr instanceof Array);
//判断obj是否等于Object
conlose.log(obj instanceof Object);
//如果正确则返回true，错误则返回false；
</script>

注意点：Array 其实也是一个Object。

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2.Array.isArray()
判断变量是否为数组

<script>
var arr = [];
var obj = {};
//conlose.log(Array.isArray(变量));
conlose.log(Array.isArray(arr));
conlose.log(Array.isArray(obj));
//正确则返回true，错误则返回false;
</script>

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3.toString
把数组转换为字符串，每一项用逗号分隔

<script>
//toString
    var arr = ["张三","李四","王五"];
    console.log(arr.toString());
</script>