ecmascript-4

How to get all Unicode characters from specific categories?

大兔子大兔子 提交于 2019-12-24 07:58:17
问题 How to get, for example..., a code point pattern like x-y\uxxxx\Uxxxxxxxxx from the Connector Punctuation ( Pc ) category, for scanning ECMAScript 3/JavaScript identifiers? Original question I need help for verifying a valid character (code point) of a ECMA-262 (3º edition, 7.6) identifier for a lexical scanner. Syntax quote Identifier :: IdentifierName but not ReservedWord IdentifierName :: IdentifierStart IdentifierName IdentifierPart IdentifierStart :: UnicodeLetter $ _ \

Why should I use string.length == 0 over string == “” when checking for empty string in ECMAScript?

旧街凉风 提交于 2019-12-22 03:07:22
问题 Most of the developers on my current project use a (to me) strange way to check for empty strings in ECMAScript: if (theString.length == 0) // string is empty I would normally write this instead: if (theString == "") // string is empty The latter version seems more readable and natural to me. Nobody I asked seemed to be able to explain the advantages of version 1. I guess that at some time in the past somebody told everybody that this is the way to do it, but now that person left and nobody

Why should I use string.length == 0 over string == “” when checking for empty string in ECMAScript?

不问归期 提交于 2019-12-05 00:15:54
Most of the developers on my current project use a (to me) strange way to check for empty strings in ECMAScript: if (theString.length == 0) // string is empty I would normally write this instead: if (theString == "") // string is empty The latter version seems more readable and natural to me. Nobody I asked seemed to be able to explain the advantages of version 1. I guess that at some time in the past somebody told everybody that this is the way to do it, but now that person left and nobody remembers why it should be done this way. I'm wondering whether there is a reason why I should choose

Why was ECMAScript 4th edition completely scrapped?

廉价感情. 提交于 2019-11-27 14:44:04
I've been looking for some information regarding the scrapped ECMAScript 4th Edition without much success, even on SO. I know Mozilla's JavaScript 1.7 implemented many (all?) of the new features offered in 4th Edition and I thought I remembered a good John Resig post on it but I can't seem to find it on his blog now. In particularly, I want to know why it was completely scrapped in favour of ECMA-262 5th Edition and why it wasn't just improved upon. Some of the features are pretty cool, like generators, iterators, let, new assignment operators and (my particular favourite) destructuring

Why was ECMAScript 4th edition completely scrapped?

做~自己de王妃 提交于 2019-11-26 16:53:02
问题 I've been looking for some information regarding the scrapped ECMAScript 4th Edition without much success, even on SO. I know Mozilla's JavaScript 1.7 implemented many (all?) of the new features offered in 4th Edition and I thought I remembered a good John Resig post on it but I can't seem to find it on his blog now. In particularly, I want to know why it was completely scrapped in favour of ECMA-262 5th Edition and why it wasn't just improved upon. Some of the features are pretty cool, like