const TemplateStringsArray for TaggedTemplateExpression #31422
Open
Description
Search Terms
TemplateStringsArray, TaggedTemplateExpression
Suggestion
There shouldn't be a type TemplateStringsArray
, it should be a const string tuple type
, so we can write code:
interface SQL<TSA, VS> {
texts: TSA;
values: VS;
}
function sql<TSA extends readonly string[], VS extends any[]>(texts:TSA, ...values: VS): SQL<TSA, VS> {
return { texts, values };
}
// then
let s: SQL<['select * from person where a=', ' and b=', ''], [number, Date]> = sql`select * from person where a=${1} and b=${new Date()}`;
Use Cases
Just like in the above code, we can test the sql at compile time or use a TypeScript Language Service Plugin (in fact, I'm writing itts-sql-plugin and then come across this problem).
Examples
Checklist
My suggestion meets these guidelines:
- This wouldn't be a breaking change in existing TypeScript/JavaScript code
- This wouldn't change the runtime behavior of existing JavaScript code
- This could be implemented without emitting different JS based on the types of the expressions
- This isn't a runtime feature (e.g. library functionality, non-ECMAScript syntax with JavaScript output, etc.)
- This feature would agree with the rest of TypeScript's Design Goals.
There is another issue is alike. #16552 (comment)
Besides, TemplateStringsArray
is ReadonlyArray<string>
, it should be const anyway.