make-transform

Make simple string based functions into browserify transforms. This does not return anything like a true stream and, as a result, is very small to browserify.

The objective was to implement just the API needed to support:

• using it as a browserify transform
• process.stdin.pipe(transform).pipe(process.stdout)
• fs.createReadStream('input.js').pipe(transform).pipe(process.stdout)
• process.stdin.pipe(transform).pipe(fs.createWriteStream('output.js'))
• fs.createReadStream('input.js').pipe(transform).pipe(fs.createWriteStream('output.js'))

In short, this is a helper for when you are forced to interface with streams by factors outside your controll, but the actual API is just processing strings (a far simpler abstraction).

Installation

npm install make-transform

API

makeTransform(fn(filename, source))

Make a browserify transform out of a function which takes filename and source as arguments and returns a string.

If a source argument is provided when called, it will just pass through to fn.

Example:

var makeTransform = require('make-transform')

module.exports = makeTransform(function (file, source) {
  return source.toLowerCase()
})

var res = module.exports('file.js', 'FUNCTION (STR) { RETURN STR.SPLIT("") }')
// res => 'function (str) { return str.split("") }'

var strm = module.exports('file.js')
strm.end('FUNCTION (STR) { RETURN STR.SPLIT("") }')
strm.pipe(concat(function (res) {
  // res => 'function (str) { return str.split("") }'
}))

makeTransform.async(fn(filename, source, callback))

Make a browserify transform out of a function which takes filename, source and callback as arguments and calls the callback with an optional error and a string.

If a source argument and callback is provided when called, it will just pass through to fn.

Example:

var makeTransform = require('make-transform')

module.exports = makeTransform.async(function (file, source, callback) {
  callback(null, source.toLowerCase())
})

module.exports('file.js', 'FUNCTION (STR) { RETURN STR.SPLIT("") }', function (err, res) {
  // res => 'function (str) { return str.split("") }'
})

var strm = module.exports('file.js')
strm.end('FUNCTION (STR) { RETURN STR.SPLIT("") }')
strm.pipe(concat(function (res) {
  // res => 'function (str) { return str.split("") }'
}))

Promises

Promise support was ommitted in an effor to keep this library ludicrously small. It's easy enough to make your own "promise transform" though:

var makeTransform = require('make-transform')
var Promise = require('promise')

function transform(file, source) {
  // return a promise for a string here
}
var streaming = makeTransform.async(Promise.nodeify(transform))
module.exports = streaming
module.exports.promise = transform

License

MIT