dotfiles/.vscode/extensions/saviorisdead.RustyCode-0.18.0/node_modules/unique-stream/index.js

55 lines
976 B
JavaScript
Raw Normal View History

2016-09-11 09:29:13 +01:00
var Stream = require('stream');
function prop(propName) {
return function (data) {
return data[propName];
};
}
module.exports = unique;
function unique(propName) {
var keyfn = JSON.stringify;
if (typeof propName === 'string') {
keyfn = prop(propName);
} else if (typeof propName === 'function') {
keyfn = propName;
}
var seen = {};
var s = new Stream();
s.readable = true;
s.writable = true;
var pipes = 0;
s.write = function (data) {
var key = keyfn(data);
if (seen[key] === undefined) {
seen[key] = true;
s.emit('data', data);
}
};
var ended = 0;
s.end = function (data) {
if (arguments.length) s.write(data);
ended++;
if (ended === pipes || pipes === 0) {
s.writable = false;
s.emit('end');
}
};
s.destroy = function (data) {
s.writable = false;
};
s.on('pipe', function () {
pipes++;
});
s.on('unpipe', function () {
pipes--;
});
return s;
}