Syntax errors after minifying unicode

[danprince]

Trying to use mathiasbynens/he to encode html entities in the browser, but after adding the library, the app has started getting syntax errors in Safari and Firefox.

The offending character seems to be a unicode character, that appears in the source after minification.

Here's the result of running the corresponding snippet of code in Babel's REPL with Babili enabled:

let a = { '\u2118':'wp' };
// becomes
'use strict';var a={℘:'wp'};

Visiting that link in Firefox 50.1.0 results in an "Illegal character error" in the REPL. Seeing as it works fine without Babili, I'm guessing this is a bug, rather than a deliberate constraint.

Pretty sure it happens in babel-plugin-transform-property-literals as it turns the string into a literal key.