Swatchjs-batch-koa NPM

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.