make file-size-builder thenable

src/file-size-resolver.ts → src/file-size-builder.ts

@@ -2,9 +2,15 @@
 
 import Fs from 'fs-extra'
 
-export type FileSizeMetric = 'bytes' | 'kilobytes' | 'megabytes' | 'gigabytes' | 'terabytes' | 'petabytes'
-
-export class FileSizeResolver {
+export type FileSizeMetric =
+  'bytes' |
+  'kilobytes' |
+  'megabytes' |
+  'gigabytes' |
+  'terabytes' |
+  'petabytes'
+
+export class FileSizeBuilder {
   /**
    * Stores the file size metric.
    */
@@ -53,6 +59,13 @@ export class FileSizeResolver {
     return this
   }
 
+  /**
+   * Returns the file size with the provided metric ("bytes" by default).
+   */
+  async then (onfulfilled: (size: number) => number): Promise<number> {
+    return this.calculate().then(size => onfulfilled(size))
+  }
+
   private async calculate (): Promise<number> {
     const stats = await Fs.stat(this.filePath)
 

src/filesystem.ts

@@ -3,7 +3,7 @@
 import Os from 'os'
 import Path from 'path'
 import { randomString, isDate } from './helper'
-import { FileSizeResolver } from './file-size-resolver'
+import { FileSizeBuilder } from './file-size-builder'
 import Lockfile, { LockOptions, UnlockOptions, CheckOptions } from 'proper-lockfile'
 import Fs, { Dirent, ObjectEncodingOptions, PathLike, SymlinkType, WriteFileOptions } from 'fs-extra'
 
@@ -25,10 +25,10 @@ export default Object.assign({}, Fs, {
    *
    * @param {String} path
    *
-   * @returns {FileSizeResolver}
+   * @returns {FileSizeBuilder}
    */
-  size (path: string): FileSizeResolver {
-    return new FileSizeResolver(path)
+  size (path: string): FileSizeBuilder {
+    return new FileSizeBuilder(path)
   },
 
   /**

test/index.js

@@ -464,6 +464,18 @@ test('isDirectory', async () => {
   ).toBe(false)
 })
 
+test('size (resolves to bytes when used as promise)', async () => {
+  const file = await ensureTempFile()
+  expect(
+    await Filesystem.size(file)
+  ).toEqual(0)
+
+  await Filesystem.writeFile(file, 'hello')
+  expect(
+    await Filesystem.size(file)
+  ).toEqual(5)
+})
+
 test('size in bytes', async () => {
   const file = await ensureTempFile()
   expect(