Javascript-map and set

The default object representation of JavaScript {} can be thought of as a Map data structure in another language Dictionary , or a set of key-value pairs.

But the JavaScript object has a small problem, which is that the key must be a string. But actually number or other data type as a key is also very reasonable.

To solve this problem, the latest ES6 specification introduces new data types Map . To test whether your browser supports the ES6 specification, execute the following code and if the browser Referenceerror error, you need to change to a browser that supports ES6:

Javascript-map and set