src/server/utilities.ts

import { getBaseFileName } from "./_namespaces/ts.js";
import {
    Logger,
    LogLevel,
    NormalizedPath,
    ServerHost,
} from "./_namespaces/ts.server.js";

/** @internal */
export class ThrottledOperations {
    private readonly pendingTimeouts = new Map<string, any>();
    private readonly logger?: Logger | undefined;
    constructor(private readonly host: ServerHost, logger: Logger) {
        this.logger = logger.hasLevel(LogLevel.verbose) ? logger : undefined;
    }

    /**
     * Wait `number` milliseconds and then invoke `cb`.  If, while waiting, schedule
     * is called again with the same `operationId`, cancel this operation in favor
     * of the new one.  (Note that the amount of time the canceled operation had been
     * waiting does not affect the amount of time that the new operation waits.)
     */
    public schedule(operationId: string, delay: number, cb: () => void): void {
        const pendingTimeout = this.pendingTimeouts.get(operationId);
        if (pendingTimeout) {
            // another operation was already scheduled for this id - cancel it
            this.host.clearTimeout(pendingTimeout);
        }
        // schedule new operation, pass arguments
        this.pendingTimeouts.set(operationId, this.host.setTimeout(ThrottledOperations.run, delay, operationId, this, cb));
        if (this.logger) {
            this.logger.info(`Scheduled: ${operationId}${pendingTimeout ? ", Cancelled earlier one" : ""}`);
        }
    }

    public cancel(operationId: string): boolean {
        const pendingTimeout = this.pendingTimeouts.get(operationId);
        if (!pendingTimeout) return false;
        this.host.clearTimeout(pendingTimeout);
        return this.pendingTimeouts.delete(operationId);
    }

    private static run(operationId: string, self: ThrottledOperations, cb: () => void) {
        self.pendingTimeouts.delete(operationId);
        if (self.logger) {
            self.logger.info(`Running: ${operationId}`);
        }
        cb();
    }
}

/** @internal */
export class GcTimer {
    private timerId: any;
    constructor(private readonly host: ServerHost, private readonly delay: number, private readonly logger: Logger) {
    }

    public scheduleCollect(): void {
        if (!this.host.gc || this.timerId !== undefined) {
            // no global.gc or collection was already scheduled - skip this request
            return;
        }
        this.timerId = this.host.setTimeout(GcTimer.run, this.delay, this);
    }

    private static run(self: GcTimer) {
        self.timerId = undefined;

        const log = self.logger.hasLevel(LogLevel.requestTime);
        const before = log && self.host.getMemoryUsage!(); // TODO: GH#18217

        self.host.gc!(); // TODO: GH#18217
        if (log) {
            const after = self.host.getMemoryUsage!(); // TODO: GH#18217
            self.logger.perftrc(`GC::before ${before}, after ${after}`);
        }
    }
}

/** @internal */
export function getBaseConfigFileName(configFilePath: NormalizedPath): "tsconfig.json" | "jsconfig.json" | undefined {
    const base = getBaseFileName(configFilePath);
    return base === "tsconfig.json" || base === "jsconfig.json" ? base : undefined;
}