Clarification on the Use of `Id` vs `Self` in `Context.Tag`

export const Tag: <const Id extends string>(id: Id) => <Self, Shape>() => TagClass<Self, Id, Shape> = internal.Tag

export const Tag: <const Id extends string>(id: Id) => <Self, Shape>() => TagClass<Self, Id, Shape> = internal.Tag

Could someone explain the relationship between

Id

Id

and

Self

Self

for

Context.Tag

Context.Tag

please?

From my understanding, the

Id

Id

is used as the key to resolve the value/implementation of

Shape

Shape

from the

Context

Context

Why is

Self

Self

ie. the class that

extends Context.Tag

extends Context.Tag

(

S1

S1

S2

S2

in the screenshot) not used as the key instead?

Assuming

Context

Context

is some kind of JS

Map

Map

under the hood, anything could be used as the key including the class itself ie.

const Context = new Map()
Context.set(S1, "a") // ie. Effect.provideService(S1, "a")
Context.set(S2, 1)   // ie. Effect.provideService(S2, 1)

const Context = new Map()
Context.set(S1, "a") // ie. Effect.provideService(S1, "a")
Context.set(S2, 1)   // ie. Effect.provideService(S2, 1)

This would circumvent the need for unique string identifiers and the issue shown in the screenshot where duplicate IDs ("S1" in the example) for different services (eg.

S1

S1

and

S2

S2

) with different interfaces/shapes resolve to whichever implementation is provided first to the

Context

Context

Effect Community•7mo ago

Matthew

Clarification on the Use of `Id` vs `Self` in `Context.Tag`

export const Tag: <const Id extends string>(id: Id) => <Self, Shape>() => TagClass<Self, Id, Shape> = internal.Tag

export const Tag: <const Id extends string>(id: Id) => <Self, Shape>() => TagClass<Self, Id, Shape> = internal.Tag

Could someone explain the relationship between

Id

Id

and

Self

Self

for

Context.Tag

Context.Tag

please?

From my understanding, the

Id

Id

is used as the key to resolve the value/implementation of

Shape

Shape

from the

Context

Context

Why is

Self

Self

ie. the class that

extends Context.Tag

extends Context.Tag

(

S1

S1

S2

S2

in the screenshot) not used as the key instead?

Assuming

Context

Context

is some kind of JS

Map

Map

under the hood, anything could be used as the key including the class itself ie.

const Context = new Map()
Context.set(S1, "a") // ie. Effect.provideService(S1, "a")
Context.set(S2, 1)   // ie. Effect.provideService(S2, 1)

const Context = new Map()
Context.set(S1, "a") // ie. Effect.provideService(S1, "a")
Context.set(S2, 1)   // ie. Effect.provideService(S2, 1)

This would circumvent the need for unique string identifiers and the issue shown in the screenshot where duplicate IDs ("S1" in the example) for different services (eg.

S1

S1

and

S2

S2

) with different interfaces/shapes resolve to whichever implementation is provided first to the

Context

Context

Clarification on the Use of `Id` vs `Self` in `Context.Tag`

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Clarification on the Use of `Id` vs `Self` in `Context.Tag`

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