Anyone have ideas on more examples? It’s tempting to make a transpiler plugin to see how it works in practice, but I’d like to see more examples first. Thanks
On Sat, Apr 25, 2020 at 1:12 PM Jacob Bloom <[email protected]> wrote: > Maybe it would be less footgunny to support autovivification in a more > class-based way, like Python does? > > ```javascript > class AutoVivArray extends Array { > [Symbol.getMissing](identifier) { > /* if we're here, identifier is not an ownProperty > * and is nowhere on the prototype chain */ > this[identifier] = new Whatever(); > return this[identifier]; > } > } > ``` > > Though I can't see how that's much more useful than Proxies besides saving > you a little boilerplate > > On Fri, Apr 24, 2020 at 3:23 PM Thomas Shinnick <[email protected]> > wrote: > >> You are describing Perl's autovivification feature. Also possible (in >> that syntax) for arrays and mixed object/array chains. I liked it, but many >> saw it as a footgun. There was even a compile time module to turn off the >> feature, if the coder wanted more caution. Having mentioned Perl I will >> assume this is DOA? >> >> On Fri, Apr 24, 2020, 14:36 Tobias Buschor <[email protected]> >> wrote: >> >>> Since we now have the "Optional Chaninig Operator" , perhaps a "Forced >>> Chaining Operator" would also be worth considering. >>> I, personally, could use it: >>> >>> let table; >>> table!.user!.id!.type = 'int' >>> >>> will evaluate to: >>> >>> let table; >>> if ( ! ( table instanceOf Object) ) table = {}; >>> if ( ! ( table.user instanceOf Object) ) table.user = {}; >>> if ( ! ( table.user.id instanceOf Object) ) table.user.id = {}; >>> table.user.id.type = 'int'; >>> >>> Also to be noted: >>> Sometimes a fallback to `Object.create(null)` or something other might >>> be desirable. >>> But since `{}` is syntactical sugar for >>> `Object.create(Object.prototype)`, this would be consistent. >>> >>> _______________________________________________ >>> es-discuss mailing list >>> [email protected] >>> https://mail.mozilla.org/listinfo/es-discuss >>> >> _______________________________________________ >> es-discuss mailing list >> [email protected] >> https://mail.mozilla.org/listinfo/es-discuss >> > _______________________________________________ > es-discuss mailing list > [email protected] > https://mail.mozilla.org/listinfo/es-discuss >
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