refactor: move cancellation to top level

bin/cmd.js

@@ -3,43 +3,51 @@
 import WikibaseRepo from './../lib/repo.js'
 import { pickLanguages, pickKeys } from './../lib/util.js'
 import { execCmd } from './../lib/exec.js'
-import { listen } from './../lib/signals.js'
+import { trap } from './../lib/signals.js'
 
-Promise.race([listen('SIGINT', 'SIGTERM', 'SIGQUIT'), (async () => {
-  const args = process.argv.slice(2)
-  if (args.length < 3) {
-    throw new Error(
-      `Expected at least 3 positional arguments to be given, but got ${args.length}, cannot continue.`
-    )
-  }
-  const [source, target, ...entities] = args
-
-  const oauth = {
-    consumer_key: process.env.TARGET_WIKI_OAUTH_CONSUMER_TOKEN,
-    consumer_secret: process.env.TARGET_WIKI_OAUTH_CONSUMER_SECRET,
-    token: process.env.TARGET_WIKI_OAUTH_ACCESS_TOKEN,
-    token_secret: process.env.TARGET_WIKI_OAUTH_ACCESS_SECRET
-  }
-  if (!Object.values(oauth).every(v => v)) {
-    throw new Error(
-      'Unable to find full set of OAuth credentials in environment variables, cannot continue.'
-    )
-  }
+Promise.race([
+  (async () => {
+    const args = process.argv.slice(2)
+    if (args.length < 3) {
+      throw new Error(
+        `Expected at least 3 positional arguments to be given, but got ${args.length}, cannot continue.`
+      )
+    }
+    const [source, target, ...entities] = args
 
-  const sourceRepo = new WikibaseRepo(source)
-  const targetRepo = new WikibaseRepo(target, { oauth })
+    const oauth = {
+      consumer_key: process.env.TARGET_WIKI_OAUTH_CONSUMER_TOKEN,
+      consumer_secret: process.env.TARGET_WIKI_OAUTH_CONSUMER_SECRET,
+      token: process.env.TARGET_WIKI_OAUTH_ACCESS_TOKEN,
+      token_secret: process.env.TARGET_WIKI_OAUTH_ACCESS_SECRET
+    }
+    if (!Object.values(oauth).every(v => v)) {
+      throw new Error(
+        'Unable to find full set of OAuth credentials in environment variables, cannot continue.'
+      )
+    }
+
+    const sourceRepo = new WikibaseRepo(source)
+    const targetRepo = new WikibaseRepo(target, { oauth })
 
-  const contentLanguages = await targetRepo.getContentLanguages()
+    const contentLanguages = await targetRepo.getContentLanguages()
 
-  let data = await sourceRepo.getEntities(...entities)
-  data = data
-    .map(e => pickKeys(e, 'type', 'labels', 'descriptions', 'aliases', 'datatype'))
-    .map(e => pickLanguages(e, ...contentLanguages))
+    let data = await sourceRepo.getEntities(...entities)
+    data = data
+      .map(e => pickKeys(e, 'type', 'labels', 'descriptions', 'aliases', 'datatype'))
+      .map(e => pickLanguages(e, ...contentLanguages))
 
-  await targetRepo.createEntities(...data)
+    await targetRepo.createEntities(...data)
 
-  console.log(`Sucessfully transferred ${entities.length} entities from ${source} to ${target}.`)
-})()])
+    console.log(
+      `Sucessfully transferred ${entities.length} entities from ${source} to ${target}.`
+    )
+  })(),
+  (async () => {
+    const signal = await trap('SIGINT', 'SIGTERM', 'SIGQUIT')
+    throw new Error(`Received ${signal}, program will exit before finishing.`)
+  })()
+])
   .then((result) => {
     process.exitCode = 0
   })

lib/signals.js

@@ -1,9 +1,7 @@
-export const listen = (...signals) => {
+export const trap = (...signals) => {
   return Promise.race(signals.map((s) => {
     return new Promise((resolve, reject) => {
-      process.on(s, () => {
-        reject(new Error(`Received ${s}, program will exit before finishing.`))
-      })
+      process.on(s, () => resolve(s))
     })
   }))
 }