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37 lines
991 B
37 lines
991 B
# inflight |
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Add callbacks to requests in flight to avoid async duplication |
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## USAGE |
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```javascript |
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var inflight = require('inflight') |
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// some request that does some stuff |
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function req(key, callback) { |
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// key is any random string. like a url or filename or whatever. |
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// |
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// will return either a falsey value, indicating that the |
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// request for this key is already in flight, or a new callback |
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// which when called will call all callbacks passed to inflightk |
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// with the same key |
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callback = inflight(key, callback) |
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// If we got a falsey value back, then there's already a req going |
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if (!callback) return |
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// this is where you'd fetch the url or whatever |
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// callback is also once()-ified, so it can safely be assigned |
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// to multiple events etc. First call wins. |
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setTimeout(function() { |
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callback(null, key) |
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}, 100) |
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} |
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// only assigns a single setTimeout |
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// when it dings, all cbs get called |
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req('foo', cb1) |
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req('foo', cb2) |
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req('foo', cb3) |
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req('foo', cb4) |
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```
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