56 lines
1.1 KiB
Plaintext
56 lines
1.1 KiB
Plaintext
'use strict';
|
|
|
|
/**
|
|
* Calculate data maxRate
|
|
* @param {Number} [samplesCount= 10]
|
|
* @param {Number} [min= 1000]
|
|
* @returns {Function}
|
|
*/
|
|
function speedometer(samplesCount, min) {
|
|
samplesCount = samplesCount || 10;
|
|
const bytes = new Array(samplesCount);
|
|
const timestamps = new Array(samplesCount);
|
|
let head = 0;
|
|
let tail = 0;
|
|
let firstSampleTS;
|
|
|
|
min = min !== undefined ? min : 1000;
|
|
|
|
return function push(chunkLength) {
|
|
const now = Date.now();
|
|
|
|
const startedAt = timestamps[tail];
|
|
|
|
if (!firstSampleTS) {
|
|
firstSampleTS = now;
|
|
}
|
|
|
|
bytes[head] = chunkLength;
|
|
timestamps[head] = now;
|
|
|
|
let i = tail;
|
|
let bytesCount = 0;
|
|
|
|
while (i !== head) {
|
|
bytesCount += bytes[i++];
|
|
i = i % samplesCount;
|
|
}
|
|
|
|
head = (head + 1) % samplesCount;
|
|
|
|
if (head === tail) {
|
|
tail = (tail + 1) % samplesCount;
|
|
}
|
|
|
|
if (now - firstSampleTS < min) {
|
|
return;
|
|
}
|
|
|
|
const passed = startedAt && now - startedAt;
|
|
|
|
return passed ? Math.round((bytesCount * 1000) / passed) : undefined;
|
|
};
|
|
}
|
|
|
|
export default speedometer;
|