same way `Object.assign` makes getters own properties, anything else special gets assigned right away, including Symbols.
This is a usually ignored gotta of the issue `Object.assign` could actually cause in the wild, specially with polyfills where WeakMap symbols assigned directly might be passed around. I'm not sure `__proto__` as key deserves any special treatment, compared to all other little gotchas, but FWIW I'm still for banning `__proto__` from the language through 1 year of browsers warnings and a wide community involvement in getting rid of that little "bomb" ECMA kept in core. NodeJS got bitten with query strings, developers loading user land JSON can get bitten with `"__proto__": null` and so on and so fort. Regards. On Wed, Sep 26, 2018 at 3:28 PM Mike Samuel <[email protected]> wrote: > Might it be a spec bug that in the below, o's prototype changes, and o.x > !== b.x? > > const a = makeIntercepter(); > const b = { x: 1 }; > const o = Object.assign( > {}, > a, > b); > > console.log(`o is plain Object: ${ Object.getPrototypeOf(o) === > Object.prototype }`); > > console.log(`b.x=${ b.x }, o.x=${ o.x }`); > > function makeIntercepter() { > return JSON.parse( > // Get an object that has an actual "__proto__" property. > '{ "__proto__": {} }', > // Replace the __proto__ property's value with one that > // traps assignment to x. > (key, value) => ( > (key === '__proto__') > ? { > set x(v) { > console.log(`intercepted ${ v }`); > }, > get x() { > return 2; > }, > } > : value)); > } > > In modern Chrome, Firefox, Safari I get > intercepted 1 > getPrototypeOf(o)===Object.prototype: false > b.x=1, o.x=2 > > _______________________________________________ > es-discuss mailing list > [email protected] > https://mail.mozilla.org/listinfo/es-discuss >
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