Thank you for this detailed write up! I believe you can help in the existing proposals!
Cheers! Ahmad Bamieh, On Wed, Dec 20, 2017 at 10:18 AM, Arash Motamedi <[email protected]> wrote: > Excellent! Thanks so much for the pointers. These will be great syntactic > improvements. > > Cheers, > Arash > > On Wed, Dec 20, 2017 at 12:12 AM, Claude Pache <[email protected]> > wrote: > >> There are already official proposals for those. See: >> >> https://github.com/tc39/proposals >> >> and search for “Nullish coalescing Operator” for the first of your >> suggestions and “Optional Chaining” for the second one. >> >> —Claude >> >> >> >> Le 20 déc. 2017 à 09:03, Arash Motamedi <[email protected]> a >> écrit : >> >> I’d like to propose two new operators that I’ve appreciated using in C#, >> with appropriate modifications for Ecmascript. >> >> ?? Null-Coalescing Operator >> >> The ?? operator is called the null-coalescing operator. It returns the >>> left-hand operand if the operand is not null or undefined; otherwise it >>> returns the right hand operand. (modified excerpt from C# definition, >>> here >>> <https://docs.microsoft.com/en-us/dotnet/csharp/language-reference/operators/null-conditional-operator> >>> .) >> >> >> Examples: >> >> let u = undefined; >> let nu = u ?? 0; >> // nu = (u !== undefined && u !== null) ? u : 0 >> >> let n = null; >> let nn = n ?? "Default"; >> // nn = (n !== undefined && n !== null) ? n : "Default"; >> >> let p = someObj.someProp ?? "Hello"; >> // p = (someObj.someProp !== undefined && someObj.someProp !== null) ? >> someObj.someProp : "Hello"; >> >> The ?? operator allows for a very terse syntactic representation of a >> rather common statement, and its value becomes very clear when evaluating >> and accessing properties on objects, as illustrated in the 3rd example >> above. For credit, comparison, and further details, please review the C# >> null coalescing operator information here >> <https://docs.microsoft.com/en-us/dotnet/csharp/language-reference/operators/null-conditional-operator> >> . >> >> >> ?. Null Conditional Member Access and ?[ Null Conditional Index Access >> >> Used to test for null or undefined before performing a member access (?.) >>> or index (?[) operation. (modified excerpt from C# definition here >>> <https://docs.microsoft.com/en-us/dotnet/csharp/language-reference/operators/null-conditional-operators> >>> .) >> >> >> Examples: >> >> let n = null; >> let nn = n?.name; >> // nn = (n.name !== null && u.name !== undefined) ? u.name : u.name; >> >> let p = {name: "John"}; >> let l = p.lastName?.length; >> // l = (u.lastName !== null && u.lastName !== undefined) ? >> u.lastName.length : u.lastName; >> >> The ?. and ?[ operators allow for graceful access (as opposed to >> null/undefined reference errors) to object members, and are particularly >> useful when used in a chained manner. For credit, comparison, and further >> details, please review the C# null conditional member access operator >> information here >> <https://docs.microsoft.com/en-us/dotnet/csharp/language-reference/operators/null-conditional-operators> >> . >> >> >> Combining the above operators can enable very concise syntax for checking >> against null/undefined and providing default values in a graceful manner. >> >> let lastNameLength = person.lastName?.length ?? 0; >> let cityToUppercase = person.address?.city?.toUpperCase() ?? "N/A"; >> >> >> Looking forward to working with the community and hopefully bringing >> these two operators to the language. >> >> Best, >> Arash >> >> _______________________________________________ >> 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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