Db requirement

Hi everyone. Effect beginner here.
I'm trying to understand how to manage Requirements (the R part of Effect<A,E,R>).

Here is what I'm trying to do (but don't know the synthax of):

Have a

queryDb<T>(query: string, params: any[])

queryDb<T>(query: string, params: any[])

function that returns a

Effect<T, MySQLError, { db: PoolConnection }>

Effect<T, MySQLError, { db: PoolConnection }>

.

To provide a more concrete situation, here is what it could look like:

export const queryDb = <T = any>(
  query: string,
  params: QueryParam[] = [],
): Effect<T, MySQLError, { db: PoolConnection }> =>
  EffectO.fromCallback(
    ({ db }, callback) => {
      db.query(query, params, callback);
    },
    (error) => new MySQLError(error as MysqlError),
  );

export const queryDb = <T = any>(
  query: string,
  params: QueryParam[] = [],
): Effect<T, MySQLError, { db: PoolConnection }> =>
  EffectO.fromCallback(
    ({ db }, callback) => {
      db.query(query, params, callback);
    },
    (error) => new MySQLError(error as MysqlError),
  );

Then outside, once it's time to run the program, we would do something like

runPromise(provideService(myProgramm, { db }))

runPromise(provideService(myProgramm, { db }))

I know the synthax isn't right, it's just to illustrate what i'm trying to do.

I saw that we are supposed to use "Context.Tag" somehow, but the examples on the website aren't sufficient for me to understand.
Can someone please help me?

Effect Community•9mo ago

Kam

Db requirement

Hi everyone. Effect beginner here.
I'm trying to understand how to manage Requirements (the R part of Effect<A,E,R>).

Here is what I'm trying to do (but don't know the synthax of):

Have a

queryDb<T>(query: string, params: any[])

queryDb<T>(query: string, params: any[])

function that returns a

Effect<T, MySQLError, { db: PoolConnection }>

Effect<T, MySQLError, { db: PoolConnection }>

.

To provide a more concrete situation, here is what it could look like:

export const queryDb = <T = any>(
  query: string,
  params: QueryParam[] = [],
): Effect<T, MySQLError, { db: PoolConnection }> =>
  EffectO.fromCallback(
    ({ db }, callback) => {
      db.query(query, params, callback);
    },
    (error) => new MySQLError(error as MysqlError),
  );

export const queryDb = <T = any>(
  query: string,
  params: QueryParam[] = [],
): Effect<T, MySQLError, { db: PoolConnection }> =>
  EffectO.fromCallback(
    ({ db }, callback) => {
      db.query(query, params, callback);
    },
    (error) => new MySQLError(error as MysqlError),
  );

Then outside, once it's time to run the program, we would do something like

runPromise(provideService(myProgramm, { db }))

runPromise(provideService(myProgramm, { db }))

Db requirement

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