leeggco / cha

Make task chaining.

cha

Make task chaining.

Cha allows tasks to be connected together into a chain that makes better readability and easier to maintain.

How to getting started?

Installing cha via NPM, this will install the latest version of cha in your project folder and adding it to your devDependencies in package.json:

npm install cha --save-dev

Touch a tasks file and naming whatever you love like build.js:

// Load cha library.
var cha = require('cha')
// Load tasks directory with an index.js that exports ./tasks/glob.js, etc.
var tasks = require('./tasks')

// Register tasks that should chaining.
cha.in('glob',     tasks.glob)
    .in('cat',     tasks.cat)
    .in('replace', tasks.replace)
    .in('write',   tasks.write)
    .in('uglifyjs',tasks.uglifyjs)
    .in('copy',    tasks.copy)
    .in('request', tasks.request)

// Define task via chaining calls.
cha()
    .glob({
        patterns: './fixtures/js/*.js',
        cwd: __dirname
    })
    .replace({
        search: 'TIMESTAMP',
        replace: +new Date
    })
    .replace({
        search: /DEBUG/g,
        replace: true
    })
    .request('http://underscorejs.org/underscore-min.js')
    .map(function(record){
        console.log(record.path)
        return record;
    })
    .cat()
    .uglifyjs()
    .write('./out/foobar.js')
    .copy('./out/foobar2.js')

Add a arbitrary command to the scripts object:

{
  "name": "cha-example",
  "scripts": {
    "build": "node ./build.js"
  },
  "devDependencies": {
    "cha": "~0.1.0"
  }
}

To run the command we prepend our script name with run:

$ npm run build

> [email protected] build 
> node ./test/build

request http://underscorejs.org/underscore-min.js
concat ./test/fixtures/bar.js,./test/fixtures/foo.js,http://underscorejs.org/underscore-min.js
write ./out/foobar.js
copy out/foobar.js > ./out/foobar2.js

How to use watch task?

var cha = require('../')
var tasks = require('./tasks')

// Set a watcher.
cha.watch = require('./tasks/watch')

cha.in('read',    tasks.read)
   .in('cat',     tasks.cat)
   .in('coffee',  tasks.coffee)
   .in('write',   tasks.write)
   .in('uglifyjs',tasks.uglifyjs)

// Start watcher.
cha.watch('./fixtures/coffee/*.coffee', {
    cwd: __dirname,
    immediately: true
}, function(filepath, event, watched){

    cha().read(watched)
        .coffee()
        .cat()
        .uglifyjs()
        .write('./out/foobar3.js')
})

To run the command we prepend our script name with run:

$ npm run watch

> [email protected] watch 
> node ./test/watch

read /test/fixtures/coffee/bar.coffee
read /test/fixtures/coffee/foo.coffee
concat /test/fixtures/coffee/bar.coffee,/test/fixtures/coffee/foo.coffee
write ./out/foobar3.js

How to enjoy cha expressions?

// Load cha library.
var cha = require('cha')
var tasks = require('./tasks')

// Register tasks that should chaining.
cha.in('glob',      tasks.glob)
    .in('request',  tasks.request)
    .in('cat',      tasks.cat)
    .in('replace',  tasks.replace)
    .in('write',    tasks.write)
    .in('uglifyjs', tasks.uglifyjs)

// Start with cha expressions.
cha(['glob:./fixtures/js/*.js', 'request:http://underscorejs.org/underscore-min.js'])
    .replace({
        search: 'TIMESTAMP',
        replace: +new Date
    })
    .replace({
        search: /DEBUG/g,
        replace: true
    })
    .cat()
    .uglifyjs()
    .write('./out/foobar.js')

To run the command we prepend our script name with run:

$ npm run expr

> [email protected] expr 
> node ./test/expr

request http://underscorejs.org/underscore-min.js
concat http://underscorejs.org/underscore-min.js
write ./out/foobar.js

How to creating custom task?

Chaining task should based on the Task.JS specification.

The following example creating a task concatenate files from the inputs. It extend from Execution class and define execute method:

var _ = require('lodash');
var fs = require('fs');
var path = require('path');
var Execution = require('execution');
var Record = require('record');

var Concat = Execution.extend({
    // Naming your task.
    name: 'concat',
    // Task description.
    description: 'Concatenate files',
    // Task options.
    options: {
        banner: {
            default: '',
            description: 'The string will be prepended to the beginning of the contents'
        },
        endings: {
            default: '\n',
            description: 'Make sure each file endings with newline'
        },
        footer: {
            default: '',
            description: 'The string will be append to the end of the contents'
        }
    },
    // Override `execution` method.
    execute: function (resolve, reject) {
        var options = this.options;
        var logger = this.logger;
        var inputs = this.inputs;

        var endings = options.endings;
        var banner = options.banner;
        var footer = options.footer;

        var paths = _.pluck(inputs, 'path');
        logger.log(this.name, paths.join(','));

        var contents = this.concat(inputs, endings);

        // Return new record object.
        resolve(new Record({
            contents: banner + contents + footer
        }));
    },
    concat: function (inputs, endings) {

        return inputs.map(function (record, index, array) {
            var contents = record.contents.toString();
            if (!RegExp(endings + '$').test(contents)) {
                contents += endings;
            }
            return contents;
        }).reduce(function (previousContents, currentContents, index, array) {
                return previousContents + currentContents;
            }, '');

    }
});

module.exports = Concat

Release History

• 2014-03-05 0.1.0 Initial release