[Feature request] allow emit param name when emitDecoratorMetadata

Search Terms

Suggestion

allow emit param name when emitDecoratorMetadata

Use Cases

class C1
{
	@d1
	m1(a: string): string
	{
		return null;
	}
}

function d1(target: Object,
	propertyKey: string,
	descriptor: TypedPropertyDescriptor<any>)
{
	return descriptor;
}

Examples

.js

class C1 {
    m1(a) {
        return null;
    }
}
__decorate([
    d1,
    __metadata("design:type", Function),
    __metadata("design:paramtypes", [String]),
    __metadata("design:paramnames", ['a']),
    __metadata("design:returntype", String)
], C1.prototype, "m1", null);
function d1(target, propertyKey, descriptor) {
    return descriptor;
}

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.

Start by reviewing the requested design:paramnames output and the emitDecoratorMetadata behavior described in the issue. The payload names no implementation files or tests, so locate the relevant compiler emission entry point and determine how the requested metadata should be specified and validated.