问题
I'm new to ECMAScript 6, and while trying to learn Ember, I've seen the following code style occassionally:
const {
abc,
def
} = Object;
I've searched Google and many sites explaining the new ES6 specifications. I know this is not the current implementation, because my console gives an error when I input that.
What does this code mean?
UPDATE
I pasted this snippet into Babel's transpiler, and this is what it returned:
"use strict";
var abc = Object.abc;
var def = Object.def;
I'm still confused as to what this is trying to accomplish.
回答1:
It is an ES2015 destructuring assignment. More specifically, it's Object Destructuring
It might help to see it rewritten in a more verbose way.
const abc = Object.abc;
const def = Object.def;
It's a syntatically terse way of extracting properties from objects, into variables.
// you can rewrite this
const name = app.name;
const version = app.version;
const type = app.type;
// as this
const { name, version, type } = app;
Browser vendors are still implementing the ES2015 specification which is probably why it didn't work in your browser.
However, there's a project called Babel which allows you to convert future specifications of Javascript back into ES5. You can try out ES2015 code in their REPL.
来源：https://stackoverflow.com/questions/33798717/javascript-es6-const-with-curly-braces