'use strict'; var format = require('./format'); /* * function cascade(formats) * Returns a function that invokes the `._format` function in-order * for the specified set of `formats`. In this manner we say that Formats * are "pipe-like", but not a pure pumpify implementation. Since there is no back * pressure we can remove all of the "readable" plumbing in Node streams. */ function cascade(formats) { if (!formats.every(isValidFormat)) { return; } return function (info) { var obj = info; for (var i = 0; i < formats.length; i++) { obj = formats[i].transform(obj, formats[i].options); if (!obj) { return false; } } return obj; }; } /* * function isValidFormat(format) * If the format does not define a `transform` function throw an error * with more detailed usage. */ function isValidFormat(fmt) { if (typeof fmt.transform !== 'function') { throw new Error(['No transform function found on format. Did you create a format instance?', 'const myFormat = format(formatFn);', 'const instance = myFormat();'].join('\n')); } return true; } /* * function combine (info) * Returns a new instance of the combine Format which combines the specified * formats into a new format. This is similar to a pipe-chain in transform streams. * We choose to combine the prototypes this way because there is no back pressure in * an in-memory transform chain. */ module.exports = function () { for (var _len = arguments.length, formats = new Array(_len), _key = 0; _key < _len; _key++) { formats[_key] = arguments[_key]; } var combinedFormat = format(cascade(formats)); var instance = combinedFormat(); instance.Format = combinedFormat.Format; return instance; }; // // Export the cascade method for use in cli and other // combined formats that should not be assumed to be // singletons. // module.exports.cascade = cascade;