ES Learning Notes

Deconstruction Assignment of variables

1. parentheses use

var [(a)] = [1];　　//报错，变量声明语句中，不能带有圆括号。
[(a)] = [1];　　　　//正确，模式是取数组的第一个成员，跟圆括号无关。

2. Traverse the map structure

Any object that has the iterator interface deployed can be for...of traversed with loops. The map structure natively supports the iterator interface, and it is convenient to get the key name and the key value with the solution assignment of the variable.

var map=NewMap(); map.Set(' First ',' Hello '); map.Set(' Second ', ' World ');  for (let [key, value] of map) {console.  Log(key + "is" + value);} //First is Hello//second            are world 

Note: Map.first = ' Hello ';
Map.second = ' world ';
Such an assignment does not have a iterator interface, so it is not possible to traverse the map and fetch the Key/value value using the above method.

 

ES Learning Notes