example mroe readable and with some typo fixed in github: https://gist.github.com/WebReflection/7059536
license wtfpl v2 http://www.wtfpl.net/txt/copying/ Cheers On Sat, Oct 19, 2013 at 11:18 AM, Andrea Giammarchi < [email protected]> wrote: > AFAIK that's also what Allen said didn't want to implement in core. An > expensive operation per each invocation due stateless loop over arbitrary > indexes. > > Although, strings are immutable in JS so I'd implement that logic creating > a snapshot once and use that as if it was an Array ... something like the > following: > > ```javascript > > !function(dict){ > > function getOrCreate(str) { > if (!(str in dict)) { > dict[str] = { > i: 0, > l: 0, > v: (Array.from || function(){ > // miserable callback > return str.split('') > })(str) > // or the for/of loop > }; > } > // times it's used > dict[str].i++; > return dict[str].v; > } > > setInterval(function () { > var key, value; > for(key in dict) { > value = dict[key]; > value.l = value.i - value.l; > // used only once or never used again > if (value.l < 2) { > // free all the RAM > delete dict[key]; > } > } > }, 5000); // 5 seconds should be enough ? > // incremental works better with > // slower timeout though > // 500 might be good too > > Object.defineProperties( > String.prototype, > { > at: { > configurable: true, > writable: true, > value: function at(i) { > return getOrCreate(this)[i]; > } > }, > // or any meaningful name > size: { > configurable: true, > get: function () { > return getOrCreate(this).length; > } > } > } > ); > > }(Object.create(null)); > > > // @example > var str = 'abc'; > alert([ > str.size, // 3 > str.at(1) // b > ]); > > > ``` > > Regards > > > > > On Sat, Oct 19, 2013 at 10:54 AM, Domenic Denicola < > [email protected]> wrote: > >> From: Mathias Bynens [mailto:[email protected]] >> >> >> > This brings us back to the earlier discussion of whether something like >> `String.prototype.codePoints` should be added: >> http://esdiscuss.org/topic/how-to-count-the-number-of-symbols-in-a-stringIt >> could be a getter or a generator… Or does `for…of` iteration handle this >> use case adequately? >> >> It sounds like you are proposing a second name for >> `String.prototype[Symbol.iterator]`, which does not sound very useful. >> >> A property for the string's "real length" does seem somewhat useful, as >> does a method that does random-access on "real characters." Certainly more >> useful than the proposed symbolAt/at. But I suppose we can pave whatever >> cowpaths arise. >> >> My proposed cowpaths: >> >> ```js >> Object.mixin(String.prototype, { >> realCharacterAt(i) { >> let index = 0; >> for (var c of this) { >> if (index++ === i) { >> return c; >> } >> } >> } >> get realLength() { >> let counter = 0; >> for (var c of this) { >> ++counter; >> } >> return counter; >> } >> }); >> ``` >> >> This would allow you to e.g. find the character in the "real" middle of a >> string with code like >> >> ```js >> var middleIndex = Math.floor(theString.realLength / 2); >> var middleRealCharacter = theString.realCharacterAt(middleIndex); >> ``` >> >> _______________________________________________ >> es-discuss mailing list >> [email protected] >> https://mail.mozilla.org/listinfo/es-discuss >> > >
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