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import { Collector } from "./collector.ts";import { Dec, Inc, Labels, Metric, Set, Value } from "./metric.ts";import { Registry } from "./registry.ts";
export class Gauge extends Metric implements Inc, Dec, Value {  private collector: Collector;  private _value?: number;
  static with(    config: {      name: string;      help: string;      labels?: string[];      registry?: Registry[];    },  ): Gauge {    const collector = new Collector(      config.name,      config.help,      "gauge",      config.registry,    );    const labels = config.labels || [];    return new Gauge(collector, labels);  }
  private constructor(    collector: Collector,    labels: string[] = [],  ) {    super(labels, new Array(labels.length).fill(undefined));    this.collector = collector;    this._value = undefined;    this.collector.getOrSetMetric(this);  }
  get description(): string {    const labels = this.getLabelsAsString();    return `${this.collector.name}${labels}`;  }
  expose(): string | undefined {    if (this._value !== undefined) {      return `${this.description} ${this._value}`;    }    return undefined;  }
  labels(labels: Labels): Inc & Dec & Set & Value {    let child = new Gauge(this.collector, this.labelNames);    for (const key of Object.keys(labels)) {      const index = child.labelNames.indexOf(key);      if (index === -1) {        throw new Error(`label with name ${key} not defined`);      }      child.labelValues[index] = labels[key];    }    child = child.collector.getOrSetMetric(child) as Gauge;
    return {      // deno-lint-ignore no-inferrable-types      inc: (n: number = 1) => {        child.inc(n);      },      // deno-lint-ignore no-inferrable-types      dec: (n: number = 1) => {        child.dec(n);      },      set: (n: number) => {        child.set(n);      },      value: () => {        return child._value;      },    };  }  // deno-lint-ignore no-inferrable-types  inc(n: number = 1) {    if (this._value === undefined) {      this._value = 0;    }    this._value += n;  }  // deno-lint-ignore no-inferrable-types  dec(n: number = 1) {    if (this._value === undefined) {      this._value = 0;    }    this._value -= n;  }
  set(n: number) {    this._value = n;  }
  value(): number | undefined {    return this._value;  }}