swatchjs-batch-koa

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An extension for swatchjs to provide a method to invoke multiple API methods at once in KOA server context.

Quick start

All you have to do is add a few lines of code to your existing swatchjs code. The sample below shows how to use the swatchjs-batch-koa with the simple API from the swatchjs and swatchjs-koa README file:

const swatch = require('swatchjs');
const swatchKoa = require('swatchjs-koa');
const batchKoa = require('swatchjs-batch-koa'); // add this line

const model = swatch({
    "numbers.add": (a, b) => Number(a) + Number(b),
    "numbers.sub": (a, b) => Number(a) - Number(b),
});
const batchModel = swatch({'batch': batchKoa(model)}); // add this line
const extendedModel = model.concat(batchModel); // optionally add this line

const app = Koa();
swatchKoa(app, extendedModel);

API reference

The batch-koa function

const batchKoa = require('swatchjs-batch-koa');

const augmentedModel = batchKoa(model, name);

Loading this library will result in a function (batchKoa in the example above) which when called will return a handler that can be used with the swatch function to produce a model for the API method that allows all other methods to be invoked in a single network call.

The function exposed by the library takes the following parameters:

Parameter	Required	Description
model	Yes	A model produced by by the swatch function (see swatchjs)
name	No	The name of the API method. Defaults to batch.

Return value

The batchKoa method returns a handler that takes the following parameters:

Parameter	Required	Description
ops	Yes	An array of operations to batch.
ops[idx].method	Yes	The method name.
ops[idx].args	Yes	An object with the arguments to pass to the method.

The methods are not guaranteed to be executed in any particular order, and they succeed or fail independently. They are however guaranteed to be returned in the order in which they are received.

The response will be an array of responses, where each response has the following properties:

Property	Present	Description
ok	Always	true if the method succeed, false otherwise.
result	Sometimes	Value returned by method handler if it succeeded and returned anything other than undefined.
error	Sometimes	Exception thrown by method handler when it failed.

Runtime errors

The following errors will be generated during runtime (when invoking the handler):

Error	Error scope	Description
invalid_request	Handler	ops parameter was not valid.
invalid_method	Operation	Specified method was not declared in the API.

Developers

Coding Style

This project follows the AirBnB Javascript Coding Guidelines using ESLint settings.