@opentelemetry/sdk-metrics
Version:
41 lines • 1.61 kB
JavaScript
/*
* Copyright The OpenTelemetry Authors
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* https://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
import { ExponentMapping } from './ExponentMapping';
import { LogarithmMapping } from './LogarithmMapping';
import { MappingError } from './types';
const MIN_SCALE = -10;
const MAX_SCALE = 20;
const PREBUILT_MAPPINGS = Array.from({ length: 31 }, (_, i) => {
if (i > 10) {
return new LogarithmMapping(i - 10);
}
return new ExponentMapping(i - 10);
});
/**
* getMapping returns an appropriate mapping for the given scale. For scales -10
* to 0 the underlying type will be ExponentMapping. For scales 1 to 20 the
* underlying type will be LogarithmMapping.
* @param scale a number in the range [-10, 20]
* @returns {Mapping}
*/
export function getMapping(scale) {
if (scale > MAX_SCALE || scale < MIN_SCALE) {
throw new MappingError(`expected scale >= ${MIN_SCALE} && <= ${MAX_SCALE}, got: ${scale}`);
}
// mappings are offset by 10. scale -10 is at position 0 and scale 20 is at 30
return PREBUILT_MAPPINGS[scale + 10];
}
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