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takeUntil #258

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0858c1d
takeUntil but test isnt working
ccorcos Mar 29, 2015
72cb224
takeUntil test works
ccorcos Mar 29, 2015
c33dd7e
takeUntil better tests
ccorcos Mar 30, 2015
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58 changes: 58 additions & 0 deletions lib/index.js
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Original file line number Diff line number Diff line change
Expand Up @@ -3554,6 +3554,64 @@ Stream.prototype.debounce = function (ms) {
};
exposeMethod('debounce');


/**
* Ends a source stream when a given stream ends or emits a value.
*
* @id takeUntil
* @section Higher-order Streams
* @name Stream.takeUntil(stream)
* @param {Stream} stream - another stream which stops the source
* @api public
*
* a = _()
* b = _()
* a.takeUntil(b)
* a.each(_.log)
* a.write(1)
* // => 1
* a.write(2)
* // => 2
* b.write(1)
* // nothing
* a.write(3)
* // nothing
*/

Stream.prototype.takeUntil = function (stream) {
if (!_.isStream(stream)) {
throw new Error('Invalid stream to takeUntil:', stream);
}
var first = true,
done = false;

return this.consume(function (err, x, push, next) {
if (first) {
stream.pull(function() {
if (!done) {
push(null, _.nil);
done = true;
}
});
first = false;
}
if (err) {
push(err);
next();
}
else if (x === _.nil) {
done = true;
push(null, x);
}
else if (!done) {
push(null, x);
next();
}
});
};
exposeMethod('takeUntil');


/**
* Creates a new Stream, which when read from, only returns the last
* seen value from the source. The source stream does not experience
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124 changes: 124 additions & 0 deletions test/test.js
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Original file line number Diff line number Diff line change
Expand Up @@ -1545,6 +1545,130 @@ exports['wrap EventEmitter (or jQuery) on handler with args wrapping by array']
});
};


exports['takeUntil'] = {
setUp: function (callback) {
this.clock = sinon.useFakeTimers();
callback();
},
tearDown: function (callback) {
this.clock.restore();
callback();
},
'invalid stream': function (test) {
test.throws(function () {
_([1,2,3]).takeUntil(10);
});
test.done();
},
'async generator': function (test) {
function delay(push, ms, x) {
setTimeout(function () {
push(null, x);
}, ms);
}
var source = _(function (push, next) {
delay(push, 10, 1);
delay(push, 20, 2);
delay(push, 30, 3);
// should be stopped
delay(push, 40, 4);
delay(push, 50, 5);
delay(push, 60, _.nil);
})
var stopStream = _(function (push, next) {
delay(push, 25, 1);
delay(push, 35, _.nil);
})
var results = [];
source.takeUntil(stopStream).each(function (x) {
results.push(x);
});
this.clock.tick(10);
test.same(results, [1]);
this.clock.tick(10);
test.same(results, [1, 2]);
this.clock.tick(10);
test.same(results, [1, 2, 3]);
this.clock.tick(10);
test.same(results, [1, 2, 3]);
this.clock.tick(20);
test.same(results, [1, 2, 3]);
test.done();
},
'toplevel - async generator': function (test) {
function delay(push, ms, x) {
setTimeout(function () {
push(null, x);
}, ms);
}
var source = _(function (push, next) {
delay(push, 10, 1);
delay(push, 20, 2);
delay(push, 30, 3);
// should be stopped
delay(push, 40, 4);
delay(push, 50, 5);
delay(push, 60, _.nil);
})
var stopStream = _(function (push, next) {
delay(push, 25, 1);
delay(push, 35, _.nil);
})
var results = [];
_.takeUntil(stopStream, source).each(function (x) {
results.push(x);
});
this.clock.tick(10);
test.same(results, [1]);
this.clock.tick(10);
test.same(results, [1, 2]);
this.clock.tick(10);
test.same(results, [1, 2, 3]);
this.clock.tick(10);
test.same(results, [1, 2, 3]);
this.clock.tick(20);
test.same(results, [1, 2, 3]);
test.done();
},
'toplevel - partial application, async generator': function (test) {
function delay(push, ms, x) {
setTimeout(function () {
push(null, x);
}, ms);
}
var source = _(function (push, next) {
delay(push, 10, 1);
delay(push, 20, 2);
delay(push, 30, 3);
// should be stopped
delay(push, 40, 4);
delay(push, 50, 5);
delay(push, 60, _.nil);
})
var stopStream = _(function (push, next) {
delay(push, 25, 1);
delay(push, 35, _.nil);
})
var results = [];
_.takeUntil(stopStream)(source).each(function (x) {
results.push(x);
});
this.clock.tick(10);
test.same(results, [1]);
this.clock.tick(10);
test.same(results, [1, 2]);
this.clock.tick(10);
test.same(results, [1, 2, 3]);
this.clock.tick(10);
test.same(results, [1, 2, 3]);
this.clock.tick(20);
test.same(results, [1, 2, 3]);
test.done();
},
'noValueOnError': noValueOnErrorTest(_.takeUntil(_()))
};

exports['sequence'] = function (test) {
_.sequence([[1,2], [3], [[4],5]]).toArray(function (xs) {
test.same(xs, [1,2,3,[4],5]);
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