JavaScript prototype class inference #5876
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# Conflicts: # src/compiler/binder.ts # src/compiler/checker.ts # src/harness/fourslash.ts
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| // Look up the function in the local scope, since prototype assignments should immediately | ||
| // follow the function declaration | ||
| const funcSymbol = container.locals[classId.text]; |
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This doesn't guarantee that the prototype assignment immediately follows. Also, what if classId denotes a non-function, such as a variable or an interface declaration? I'm thinking you should instead check that the prototype assignment is immediately contained in a statement list and that the immediately preceding statement is a function declaration.
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I'm thinking that the kind of inference you're doing should also apply when you access |
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Added |
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@ahejlsberg any other comments? |
| // in a JS file | ||
| const funcSymbol = checkExpression(node.expression).symbol; | ||
| if (funcSymbol && funcSymbol.members && (funcSymbol.flags & SymbolFlags.Function)) { | ||
| return createAnonymousType(undefined, funcSymbol.members, emptyArray, emptyArray, /*stringIndexType*/ undefined, /*numberIndexType*/ undefined); |
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You need to create this type once and cache it. Right now you're creating a brand new type every time which allocates a lot of objects and defeats all the type comparison caching we do.
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JavaScript prototype class inference
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Cleanup of #5578 that is based to the appropriate branch