op

v1.0.0

We follow [breaking].[feature].[fix] versioning

npm install --save @krab/op

This module provides a building-block for domain logic. Any software can be writtent using op in such a way that all of the domain logic in the software will be completely unit-testable. Usage given below.

Usage

import Op from '@krab/op'; // in projects with ES7 modules
const  Op = require('@krab/op/common'); // in projects with common JS modules

const domainOp = new Op(({db, api}) => {
  return db.getResults() // returns a promise
    .then((dbResults) => api.processData(dbResults))
  ;
});

// OR

const domainOp = new Op(async ({db, api}) => {
  const dbResults = await db.getResults();
  const apiResults = await api.processData(dbResults);

  return apiResults;
}, { // this param is optional
  doc: 'Does somthing with db and api',
  types: {
    db: (db) => db instanceof Db,
    api: (api) => api instanceof Api
  }
});

domainOp.mount({db: new Db(config.db), api: new Api(config.api)});
const results = await domainOp.run();
domainOp.run().then((results) => {});

// OR

domainOp.run({db: new Db(config.db), api: new Api(config.api)});

Features

1. An op is either async, or returns a Promise.
2. Failure to comply with 1. will result in a runtime-error.
3. An op can have a doc string attached to it.
4. An op can have types associated with it, which will be used to validate the params supplied to the op.
5. An op can be run in 2 ways: op.run(params) or op.mount(params).run().
6. op.mount mounts a set of params in the op, so that op.run can be called without any arguments.
7. An op can be cloned using op.clone().
8. An op.vent is an event-aggregator on which the events 'start', 'err', 'done', and 'end' are emitted at appropriate times in the lifecyclt of the op.

Op Events

op uses @krab/vent(link). Each instance of class Op has a property vent, which is an event aggregator attached to that instance. Usage of op.vent given below.

const op = new Op(...);

op.vent.on('start', ({op, params}) => {...});
op.vent.on('err', ({op, err, params}) => {...});
op.vent.on('done', ({op, result, params}) => {...});
op.vent.on('end', ({op, success, params}) => {...});