node-yieldin

An easy interactive way to use Readable/Writable streams (I/O streams) with yield in a generator function.

Install

npm install github:accup/node-yieldin

or

npm install accup/node-yieldin

will be available.

Examples

Use it as interactive I/O

The keyword yield works as a keyword of interactive I/O.

• main generator can obtain a parameter which is a function to write chunk to stream.
• yield returns null when the istream has ended.

var yieldin = require('yieldin');

/**
 * any I/O streams
 */
var readable, writable;

/**
 * The first argument should be readable stream.
 * The second argument should be writable stream.
 * The third argument should be generator function (function *).
 */
yieldin.run(readable, writable, function * (write) {
	// Write "xxx" to writable stream.
	write("xxx");
	// Read a chunk from readable stream.
	var chunk = yield;

	// --------------------------------------
	// Next statement is the same as previous statements.
	var chunk = yield "xxx";
});

Use it as interactive standard I/O (stdin/stdout)

yieldin.stdrun(main) is similar with yieldin.run(stdin, stdout, main), but, in the yieldin.stdrun,

• always call stdin.setEncoding('utf8').
• yield returns a word (for example, when getting chunk "a b c", yield first returns "a" and secondly returns "b", ...).
• write function has 2 parameters. The second parameter is line-terminator (like '\r\n') (default is os.EOL).

var yieldin = require('yieldin');

yieldin.stdrun(function * (write) {
	// Question and Answer
	// For no line-terminator writing, assigning "" to the second param.
	write("What's your favorite food? ", "");
	var food = yield;
	write(`Oh, '${food}', that's nice!`);

	// Shorthand of Q&A
	// In contrast, `yield` writing has no line-terminator.
	var food = yield "What's your favorite food? ";
	write(`Oh, '${food}', that's nice!`);

	// Very-shorthand of Q&A
	write(`Oh, '${yield "What's your favorite food? "}', that's nice!`);
});
// [result (maybe)]
// What's your favorite food? sushi
// Oh, 'sushi', that's nice!
// What's your favorite food? 寿司
// Oh, '寿司', that's nice!
// What's your favorite food? 🍣
// Oh, '🍣', that's nice!

Logs

• Restore this repository 2018/05/29
• Ver1.0.2
  • Update yield operation. yield returns null when a istream (readable stream) has ended.
  • Fix a small bug. The older version of stdrun(main) refered run(istream, ostream, main) as this.run, then if run was assigned to another variable, this didn't refers yieldin and run threw an error.

Old logs

• Ver1.0.1
  • The second parameter of write(chunk, end) in stdrun supported, then run(stdin, stdout, main) & stdrun(main) became different.
• Ver1.0.0
  • Both run(stdin, stdout, main) & stdrun(main) are the same operation.

Remarks

• This is a repository to consider making an npm package.