weldy

A sort of pipe operator (|>) implementation for Node.js based on co.

weldy takes a value and an array with the following structure [ [fn_1, ...args], [fn_2, ...args], ... ,[fn_n, ...args] ], processes each element invoking fn, using as first argument the output of the previous one (if it returns any value) and the ...args. It returns a promise. The first argument of the first function can be passed as the first weldy param.

Examples

Simple arithmetical operations:

weldy(5, [  // first argument for sqrt function
  [ square ],
  [ sum, 3, 4, 5 ],
  [ sub, 4 ],
  [ console.log ] // 33
])

CRUD operations on mongodb:

function insert () {
    return db.collection('document').insertMany([
      { value: 'object1' },
      { value: 'object2' },
      { value: 'object3' }
    ])
}
 
function retrieve (value) {
  return db.collection('document').find({ value }).limit(1).next().then(object => object.value)
}
 
function update (value, newValue) {
  console.log(`Update collection: ${value} -> ${newValue}`)
  return db.collection('document').updateOne({ value }, { $set: { value: newValue } })
}
 
function isOk (object) {
  console.log(`Update ok: ${object.result.ok}`)
}
 
insert()
 
weldy('object1', [
  [ retrieve ],
  [ update, 'object0' ],
  [ isOk ]
])

Usage with node-fetch:

weldy('http://github.com', [
  [ fetch ],
  [ res => res.text() ],
  [ console.log ]
])

API

weldy(value, [[ [fn_1, ...args], [fn_2, ...args], ... ,[fn_n, ...args]] ]).then( val => )

where value is the first argument of the first function (// TODO: to improve).

License

MIT