es6 Null conduction operator - es6 Null conduction operator

Question

How to use the Null conduction operator in Ruan Yifeng es6.

const firstName = message?.body?.user?.firstName || 'default';

写了这句之后直接编译出错了。

Answer 1

This syntax is js 的么？感觉是 coffee 的，即使 js 有，应该也得有引入对应的presets 到babel，es6好像没有这种语法，引入最新的babel presetTry to see if it can be compiled

Answer 2

Mentioned in the article. "Null Conduction Talisman" is just a proposal. Babel is not displayed yet.