Improve typings

Change-type: patch

lib/preload.ts

@@ -250,7 +250,7 @@ export class Preloader extends EventEmitter {
  stderr = new streamModule.PassThrough();
  bufferedStderr = new BufferBackedWritableStream();
  dockerPort;
- container;
+ container: Awaited<ReturnType<typeof createContainer>> | undefined;
  state; // device state from the api
  freeSpace: number | undefined; // space available on the image data partition (in bytes)
  preloadedBuilds: string[] | undefined; // list of preloaded Docker images in the disk image
@@ -340,7 +340,7 @@ export class Preloader extends EventEmitter {
  });
  }
 
- async _runWithSpinner(name, fn) {
+ async _runWithSpinner<T>(name: string, fn: () => (T | Promise<T>)): Promise<T> {
  this._startSpinner(name);
  try {
  return await fn();
@@ -719,10 +719,10 @@ export class Preloader extends EventEmitter {
  )}/blobs/${layerDigest}`;
  }
 
- async _getApplicationImagesManifests(imagesLocations, registryToken) {
+ async _getApplicationImagesManifests(imagesLocations: string[], registryToken: string) {
  return await limitedMap(
  imagesLocations,
- async (imageLocation: string) => {
+ async (imageLocation) => {
  const { body } = await this.registryRequest(
  {
  registryUrl: this._registryUrl(imageLocation),
@@ -739,7 +739,7 @@ export class Preloader extends EventEmitter {
  );
  }
 
- async _getLayersSizes(manifests: Manifest[], registryToken) {
+ async _getLayersSizes(manifests: Manifest[], registryToken: string) {
  const digests = new Set();
  const layersSizes = new Map();
  const sizeRequests: Array<{ imageLocation: string; layer: Layer }> = [];
@@ -862,7 +862,7 @@ export class Preloader extends EventEmitter {
  if (this.application || !appId) {
  return;
  }
- return this._runWithSpinner(`Fetching application ${appId}`, async () => {
+ await this._runWithSpinner(`Fetching application ${appId}`, async () => {
  const releaseFilter: PineFilter<Release> = {
  status: 'success',
  };
@@ -912,14 +912,14 @@ export class Preloader extends EventEmitter {
  });
  }
 
- async _checkImage(image) {
+ async _checkImage(image: string) {
  const ok = await isReadWriteAccessibleFile(image);
  if (!ok) {
  console.warn('The image must be a read/write accessible file');
  }
  }
 
- _pluralize(count, thing) {
+ _pluralize(count: number, thing: string) {
  return `${count} ${thing}${count !== 1 ? 's' : ''}`;
  }
 
@@ -961,7 +961,7 @@ export class Preloader extends EventEmitter {
  );
  this.container = container;
  await this._runWithSpinner('Starting preloader container', () =>
- this.container.start(),
+ container.start(),
  );
 
  for (const certificate of this.certificates) {
@@ -1014,7 +1014,7 @@ export class Preloader extends EventEmitter {
 
  _ensureCanPreload() {
  // Throws a BalenaError if preloading is not possible
- let msg;
+ let msg: string | undefined;
 
  // No releases
  if (this.application.owns__release.length === 0) {
@@ -1164,6 +1164,6 @@ export class Preloader extends EventEmitter {
  this.appId = appIdOrSlug;
  this.commit = commit;
  this.application = null;
- return await this._fetchApplication();
+ await this._fetchApplication();
  }
 }