When performing many asynchronous operations in javascript, nested callbacks can become difficult to read and maintain. Api-chain is a very light and easy to use interface for creating a fluent synchronous style API for control flow of asynchronous javascript. It is packaged as a commonJS module through NPM but not only works with Node.js, but has been tested and works with PhantomJS as well.
Methods can pass values down the chain by invoking next with them, e.g. next(null, value). Node.js callback style methods will be wrapped automatically so as to pass the results down the chain.
npm install api-chain
// require api-chain module
var api = require('api-chain');
// define your api by passing methods to create
var fs = api.create({
read: require('fs').readFile,
toString: function (data, next) {
next(null, data.toString());
},
view: function (contents) {
console.log(contents);
}
});
// example using the chainable 'fs' API as created above
fs.read('./index.js')
.toString()
.view();
For more examples look in the examples subdirectory.
name | type | default | description |
---|---|---|---|
onError | fn | undefined | called when error is emitted unless error method is overwritten |
throwErrors | bool | true | whether to throw unhandled errors (ignored if onError exists) |
continueErrors | bool | false | whether to resume execution of commands after errors occur |
api.wait(n) - pause execution flow for n milliseconds
api.until(fn) - wait until callback fn returns true before continuing execution flow
api.chain(fn) - add callback fn to be executed next in the control flow stack.
- callback signature: fn([arg1,] [arg2,] ... [arg n,] [next])
api.set(name, value, [immediate]) - set api object property name to value
- if the immediate flag is set, the value will be set immediately rather than within the control flow
The following methods execute immediately (rather than within the control flow) and always return the api object
api.setOption(option, value) - set option to value
api.setOptions(options) - set several options at once based on options collection of key/value pairs
to test you will need the dev dependencies installed. Just cd to the directory api-chain is installed in and type
npm install
when installation of the dependencies completes, type
npm test
MIT Style License - see license.txt