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52 lines
2.1 KiB
JavaScript
52 lines
2.1 KiB
JavaScript
// Example to log traffic data at intersections for the city of San Francisco.
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// Log license plates of each car scanned at each intersection and add to the intersections Hyperloglog.
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// Reference: https://www.youtube.com/watch?v=MunL8nnwscQ
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import { createClient } from 'redis';
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const client = createClient();
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await client.connect();
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// Use `pfAdd` to add an element to a Hyperloglog, creating the Hyperloglog if necessary.
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// await client.pfAdd(key, value) // returns 1 or 0
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// To get a count, the `pfCount` method is used.
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// await client.pfCount(key)
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try {
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// Corner of Market Street (ID: 12) and 10th street (ID:27).
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await client.pfAdd('count:sf:12:27', 'GHN34X');
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await client.pfAdd('count:sf:12:27', 'ECN94Y');
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await client.pfAdd('count:sf:12:27', 'VJL12V');
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await client.pfAdd('count:sf:12:27', 'ORV87O');
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// To get the count of Corner of Market Street (ID: 12) and 10th street (ID:27).
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const countForMarket10thStreet = await client.pfCount('count:sf:12:27');
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console.log(`Count for Market Street & 10th Street is ${countForMarket10thStreet}`);
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// Count for Market Street & 10th Street is 4.
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// Corner of Market Street (ID: 12) and 11 street (ID:26).
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await client.pfAdd('count:sf:12:26', 'GHN34X');
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await client.pfAdd('count:sf:12:26', 'ECN94Y');
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await client.pfAdd('count:sf:12:26', 'IRV84E');
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await client.pfAdd('count:sf:12:26', 'ORV87O');
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await client.pfAdd('count:sf:12:26', 'TEY34S');
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// To get the count of Corner of Market Street (ID: 12) and 11th street (ID:26).
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const countForMarket11thStreet = await client.pfCount('count:sf:12:26');
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console.log(`Count for Market Street & 11th Street is ${countForMarket11thStreet}`);
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// Count for Market Street & 11th Street is 5.
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// To merge the Hyperloglogs `count:sf:12:26` and `count:sf:12:27`.
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await client.pfMerge('count:merge', ['count:sf:12:27', 'count:sf:12:26']);
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const countMerge = await client.pfCount('count:merge');
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console.log(`Count for the merge is ${countMerge}`);
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// Count for the merge is 6.
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} catch (e) {
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// something went wrong.
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console.error(e);
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}
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client.close();
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